vb net database assignment

• Getting started with Visual Basic .NET Language
• Environment Setup
• Program Structure
• Basic Syntax
• Functions and Subs
• Classes and Objects
• Module Statement
• Constructors
• Access Modifiers
• For Next Loop
• For Each Loop
• While End Loop
• With End With Statement
• Exit Statement
• Continue Statement
• GoTo Statement
• Conditional Statements
• Select Case
• Collections
• Exception Handling
• File Handling
• Windows Forms Application
• Basic Controls
• Events Handling
• Inheritance
• Polymorphism
• Abstract Class
• Regular Expressions
• Database Operations
• BackgroundWorker
• ByVal and ByRef keywords
• Connection Handling
• Data Access
• Debugging your application
• Declaring variables
• Dictionaries
• Disposable objects
• Error Handling
• Extension methods
• File/Folder Compression
• Google Maps in a Windows Form
• Introduction to Syntax
• Multithreading
• NullReferenceException
• OOP Keywords
• Option Explicit
• Option Infer
• Option Strict
• Reading compressed textfile on-the-fly
• Short-Circuiting Operators (AndAlso - OrElse)
• Task-based asynchronous pattern
• Type conversion
• Unit Testing in VB.NET
• Using axWindowsMediaPlayer in VB.Net
• Using BackgroundWorker
• Using Statement
• Visual Basic 14.0 Features
• WinForms SpellCheckBox
• Working with Windows Forms
• WPF XAML Data Binding

VB.NET Database Operations

Fastest entity framework extensions.

Nowadays, you can't imagine any application without a database. If your application needs to access data from the database, you will need to perform some database operations.

• In any programming language, accessing Data from a database is one of the important aspects.
• It is an absolute necessity for any programming language to have the ability to work with databases.
• VB.NET can work with a majority of databases, the most common database is Microsoft SQL Server.

SqlConnection

VB.NET provides a SqlConnection class that represents a connection to a SQL Server database, it cannot be inherited.

• A SqlConnection object represents a unique session to a SQL Server data source.
• With a client/server database system, it is equivalent to a network connection to the server.
• It is used together with SqlDataAdapter and SqlCommand to increase performance when connecting to a Microsoft SQL Server database.

To use these functionalities, we need to install System.Data.SqlClient NuGet package by running the following command in Package Manager Console .

Create Database

To create a database, let's open the SQL Server Object Explorer , expand the SQL Server and right-click on the Databases and select the Add New Database .

It will open the Create Database dialog.

Enter the database name such as MyTestDb and click the Ok button. Now right-click on the newly created database and select New Query... It will open the query editor, let's run the following script in the query editor.

It will create a table with the name Authors and add three records to that table. To check the data in the database table, right-click on the Authors table in SQL Server Object Explorer .

Select the View Data option, and it will display all the records.

Connect Database

To connect to the SQL database, you can use the following code.

The above code will create a new connection to the SQL Server database that will be connected using the connection string. To ensure that connections are always closed, open the connection inside of a using block.

Read Data From Database

Let's add some code to read data from the database we created.

Let's run the above code, and you will see the following output.

Write Data to Database

Now let's insert one more record into the database and then read all the records using the following code.

Let's run the above code and you will see the following output.

For more information about file handling, visit https://docs.microsoft.com/en-us/dotnet/api/system.data.sqlclient.sqlconnection

All the examples related to the database operations are available in the DatabaseOperations.cs file of the source code. Download the source code and try out all the examples for better understanding.

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Chapter 25 Databases with VB.NET

• the nature of simple databases and the SQL language;
• how SQL can be used with VB;
• the VB classes which provide database access.

Introduction

• as one of its tasks, the VB program needs some form of data store, and a database is most suitable.
• the programmer wishes to take advantage of the power of VB and its classes to provide a more powerful interface to a database than a conventional stand- alone database product allows.

The elements of a database

• The table is made up of a collection of similar records . In the above, we have represented each record as a row.
• A record is made up of a number of fields . In the above, we have three fields, named Artist , Company , and Sales . Effectively, a field name is a column name.
• The assumption has been made that artist names are unique, so we used this as the primary key. However, if the table contained for example student names in a college, we would have to introduce a unique student I.D number. For the above table, we set up the Artist field as the primary key when we created it, and this prohibits us from introducing other artists with the same name.

The SQL language - introduction

The select statement.

• select Artist from Artists This returns an item from every Artist field in the Artists table (i.e. the complete Artist column).
• select * from Artists This returns the items from every field in the Artists table. Effectively, it returns the complete table.
• select * from Artists where Company = 'Media Ltd' returns only the records from Artists where the company is Media Ltd . We enclose strings in single quotes. Strings are case- sensitive, so use capitals where they were used in the original database.
• select * from Artists where Sales > 20 Returns only those records with sales above 20. Note that there are no quotes around numbers. The available operators are > = = where <> means 'not equals'.
• select * from Companies where Company = 'ABC Co' This returns the single record from Companies , involving ABC Co
• select * from Artists order by Sales asc The order by item can be added to any selection. We can use asc or desc to specify ascending or descending order. The above statement puts the records in ascending order of sales.

The insert statement

The delete statement, the update statement, the vb database classes, the oledbconnection class, the oledbdataadapter class, commandtext, executenonquery, updatecommand, deletecommand, insertcommand, the datatable class.

• rows and columns are numbered from 0 upwards.
• The data table holds instances of the class Object , so when we extract an item, we convert it to the appropriate type. (For example we convert an item to a String if it is to be displayed in a text box.)

The DataGrid class

The oledbcommandbuilder class, creating a database program.

• Create a new project. Wait until the blank form appears.
• View | Server Explorer
• Right-click on Data Connections , then choose Add Connection...
• A Data Link Properties windows appears. Select Provider at the top, then select the appropriate provider for your database. (For Microsoft Access databases, choose Microsoft Jet 4.0) , then click Next
• The Connection tab appears. At step 1 , browse to your database file, and select it.
• Delete Admin from the User name text box.
• Move to the Server Explorer window, and left-click on Data Connections . The file name that you selected should appear. (Double- clicking on the name allows you to examine the database.)
• Now we add the data connection to the program. Click on the name of your database file in the Server Explorer window, and drag it onto your form. An object named OleDbConnection1 appears in the system tray.
• close the Server Explorer window, and view the toolbox. Instead of selecting Windows Forms, choose Data
• Place an OleDbDataAdapter on the form. (Assuming you have an Access database). A wizard opens up.
• The wizard can create SQL commands for you. We will write our own, but the wizard steps must be followed. Click Next
• Ensure that your data connection is selected in the drop-down list. Click Next .
• Ensure the Use SQL Statements is selected, and click Next .
• On the Generate the SQL statements pane, choose Query Builder... An Add Table window appears.
• Select one of your data tables (any one will do) and click Add , then Close .
• A list of all the fields of the chosen table appears. Put a tick against All Columns . Click OK
• An SQL Select query is shown. Click Finish .

Example - database manipulation

• The user-interface is not error-proofed. For example, an insert can be attempted even if all the fields are empty. The omission is intentional, to avoid obscuring the database code.
• To create the program, follow the setting-up process for the data connection and data adapter. Then create the GUI and enter the code. The three text boxes have been renamed to ArtistBox , CompanyBox , and SalesBox .
• Every time we create an SQL command, we display it in SQLLabel at the bottom of the form, before executing the command. The reason is that, although the VB compiler makes detailed checks on your VB coding, it does not check the contents of strings, and knows nothing about SQL. Thus, SQL statement errors are only detected at run-time, and it is useful to have a display of the SQL code. Many errors are simple mistakes with single quotes.
• It is essential to use exception-handling. In this program, we display the Message property, which provides an explanation of any errors.
• When deleting, inserting, and updating, we need to open and close the connection. We place the Close call within the Finally of the exception-handling code, so that it is performed whatever happens within the Try .

Example - the data grid

• To create the program, follow the setting-up instructions for the data connection and data adapter.
• Place a data grid on the form. It can be found in the toolbox.
• The data table is declared as a Private variable, because it is shared by both methods.
• The DataSource property of the grid is used to bind table . This means that when table changes (via the Fill method) then the table is re- displayed in the grid automatically
• To update a record, type in the new values.
• To insert a new record, type it at the bottom of the grid, alongside the * .
• To delete a record, click the button at the left of the record. This highlights all the fields. Press the delete key on the keyboard to delete it.
• To resize the columns, place the mouse between the buttons at the top of the columns, and drag.
• To sort the records based on a particular column, click the button at the top of a column. Clicking again changes from ascending order to descending order.
• The program does not check for errors after each modification of the data grid. For example, if the user enters a company that does not already exist in the Companies table, then this error will only come to light when we click Save . Thus, exception-handling is essential at the saving stage.

Programming principles

Programming pitfalls.

• It is very easy to make errors when creating SQL strings. Take care with single-quotes, and, when debugging, display the SQL command.
• When executing queries with Fill , you do not need to use Open and Close . In every other case, they are needed.

Grammar spot

• The Rows property of a data table takes two bracketed integer expressions, and returns an Object . We convert it to our required type, as in: Dim n As Integer = CInt(table.Rows(3) (4))

New language elements

New ide facilities.

• We have used the ADO.NET classes to access databases.
• A range of databases can be accessed, not only those created by Microsoft Access.
• The basic approach is to create and execute strings containing SQL statements.

VB.NET SQL Examples for Querying Databases Efficiently

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VB.NET offers a streamlined approach to database operations, with a robust framework. Using its power, you can obtain relevant information quickly and with minimal effort.

Take a look at some practical examples that show how to use VB.NET to perform SQL queries, and see how you can ensure data retrieval is both effective and efficient.

Setting Up Your Local SQL Server

Start by setting up a SQL server to review everything step by step. In the examples below you will see a Windows environment, but if you are using a different operating system like Linux and have a different SQL server, don’t worry; the general logic will remain the same.

Due to its simplicity and zero configuration approach, SQLite is an excellent choice for beginners.

To set things up, create a new folder, then open a command prompt and navigate to it. Run the following command to create a new .NET project in which you can use the VB.NET language:

You now have a project called MyVBApp . Continue the setup by integrating the SQLite package into your VB.NET project using NuGet, a popular package manager for .NET. Run this command:

After you’ve added SQLite, you can set up a local database effortlessly.

You can find all the code for these examples in the project’s GitHub repository .

Download the InitializeDatabase.vb file from the project’s repository. This particular file will help you configure your database. As you can see in this file there are some users and users' countries. You can use this as a sample database.

The command you used to create the VB.NET project created a file named Program.vb . Open this file and update it as follows:

Run this program and you should see it create a file named mydatabase.db . This is the simple database that you will use in the following examples.

Establishing a Database Connection With SQL in VB.NET

Establishing a connection using SQLite in VB.NET is straightforward. Continue editing the Program.vb file and remove the existing contents of the Main subroutine. This file serves as the project's core.

You can define a connection to the database file, mydatabase.db, with this line of code:

Data Source specifies the database file name. If the file doesn't exist, SQLite will create a new database when it establishes a connection.

The next step is to use the SQLiteConnection class to create a connection instance. You should always use a Using block when working with database connections to avoid potential leaks or deadlocks:

The Using block ensures that the connection is automatically closed when it completes.

Your final Program.vb file should look something like this:

This code will connect to the mydatabase.db database and print a confirmation message when it succeeds. If an error occurs, it will print details to the console.

How to Fetch Data and Load It Into an Array

The SELECT SQL command is the main way of fetching data from an SQL database. If you have a table named Users in your database and you want to get the Name field from every record in that table, use SELECT like this:

You can pull data from the database and load it into an array by adding this query to the Program.vb file:

You’ll see a list of names on the console, corresponding to the contents of your database table:

This code loads the data into a List structure—which has a dynamic size—before converting it to an array on completion. This approach is very useful for situations where you do not know in advance the number of records you’ll retrieve.

How to Use INSERT to Add Data to a Database

You can use the INSERT INTO command to add new data to a database. For example, consider the Users table that has two columns named Name and Country .

The basic SQL query you can use to add a new user would be:

To add a new user to the database using this query, update the Program.vb file as follows:

This simple example uses string interpolation to build the query, but you should avoid this in production code since it’s vulnerable to SQL injection . The alternative is parameterized queries which make database operations safer and more efficient.

Parameterized queries use placeholders, instead of direct string concatenation, to add values to SQL queries. This approach will help you avoid many security threats:

Any Other Tips for Working With a Database From Within VB.Net

Database operations in VB.NET might initially seem daunting, but with a few guidelines, you can easily master the basics.

• Use parametrized queries to guard against security vulnerabilities.
• Always close your database connection when you’ve finished fetching or updating data.
• Maintain your database to optimize its structure as your data model changes over time.
• Don't forget to make backup copies in case of emergencies.

As with any technology, databases evolve. Software gets updated, new tools emerge, and we discover better ways of doing things. It's a good idea to stay informed and updated. Some tools act as intermediaries, like Entity Framework , making it easier to write database-related code.

How to Take Your VB.NET Journey Further

VB.NET, with its deep-rooted connection to the Microsoft ecosystem, is both robust and user-friendly. To truly grasp its power, start with the official documentation provided by Microsoft. From there, explore online courses, forums, and communities, where experienced developers share their knowledge and insights.

Remember, every expert was once a beginner. With consistent effort, curiosity, and the right resources, you'll soon find yourself navigating VB.NET with confidence and ease. As you progress, don't hesitate to experiment, ask questions, and—most importantly—enjoy the process of discovery.

• Programming
• Visual Basic Programming

Lesson 23 Creating a Database Application

23.1 creating simple database application.

Visual Basic provides the capability to effectively manage databases created with various database programs, including MS Access, Oracle, MySQL, and more. In this lesson, our focus is not on database file creation, but rather on accessing database files within the VB environment. To illustrate this concept, we will develop a straightforward database application that allows users to browse customer names. In the following example, we will create a simple database application which enables one to browse customers' names.  To create this application,  select the data control on the toolbox(as shown in Figure 23.1) and insert it into the new form. Place the data control somewhere at the bottom of the form. Name the data control as data_navigator . To be able to use the data control, we need to connect it to any database. We can create a database file using any database application but I suggest we use the database files that come with VB6. Let's select NWIND.MDB as our database file.

23.2 Connecting Data Control to Database

To connect the data control to this database, double-click the DatabaseName property in the Properties window and then click on the button with three dots on the right(as shown in Figure 23.2) to open a file selection dialog as shown in Figure 23.3. From the dialog, search the folders of your hard drive to locate the database file NWIND.MDB. It is usually placed under Microsoft Visual Studio\VB98\ folder, Select the aforementioned file and now your data control is connected to this database file.

The next step is to double-click on the RecordSource property to select the customers table from the database file NWIND.MDB, as shown in Figure 23.4. You can also change the caption of the data control to anything, we use Click to browse Customers. After that, we will place a label and change its caption to Customer Name. In addition, insert another label and name it as cus_name and leave the label empty as customers' names will appear here when we click the arrows on the data control. We need to bind this label to the data control for the application to work. To do this, open the label's DataSource and select data_navigator that will appear automatically. One more thing that we need to do is to bind the label to the correct field so that data in this field will appear on this label. To do this, open the DataField property and select ContactName, as shown in Figure 23.5.

Now, press F5 and run the program. You should be able to browse all the customers' names by clicking the arrows on the data control, as hown in Figure 23.7.

The Design Interface.

You can also add other fields using exactly the same method. For example, you can add title, company, adress, City, postcode ,telephone number and more to the database browser. Besides, you can design a more professional interface, as shown in Figure 23.8.

Figure 23.8

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How to Connect Access Database in VB.Net

Database access in vb.net.

Applications talk to a database in two ways: first, to get the data stored there and show it in a way that’s easy to understand, and second, to update the database by adding , Updating , or removing data .

Microsoft ActiveX Data Objects.Net (ADO.Net) is a model that is part of the .Net framework .

Data Provider

The following four things make up the ADO.Net data provider :

How to Connect Access Database in VB.net

Time needed:  20 minutes

In this final step, we will start adding functionality to our vb.net program by adding some functional codes.

Code To Connect Access Database in VB.Net

Double the “Form1” and add the following code under “Public Class Form1” .

Inside OledbConnection , we pasted the connection string we copied from the “Step 11” instructions.

Test the Connection of Access database in VB.Net

To test the connection between the MS access database and VB.Net , Double click form1 a nd add the following code under “Form1_Load” events.

How to Load Record from Access Database to Datagridview In VB.Net

In this section, we will learn how to load a record from the Access database to Datagridview using vb.net . To start with, double-click the “ Load record” button and add the following code.

After adding the code, you may press F5 or click the Start debugging button to test the code. The output should look like as shown below.

Save Record in Access Database using VB.net

Updating of records from access database in vb.net.

In this section, we will learn how to update records from an access database using vb.net . In order for us to proceed in updating the record , we will add first a code to pass value from datagridview to textboxes.

So here’s the following code.

Only the Query is different.

Deleting of Records from Access Database In VB.Net

After this process, you can now run the program to test if all the codes in this tutorial are working well.

Watch the full video tutorial about How to Connect to an Access Database in VB.NET until the end to see the bonus techniques and apply them to your project.

Download the vb.net project full Source code Below.

Frequently Asked Questions

The data provider is used to connect to a database. Executing commands and retrieving data, storing it in a Dataset, reading the retrieved data, and updating the database.

This is integral to the working of ADO.Net since data is transferred to and from a database through a data adapter. It retrieves data from a database into a dataset and updates the database. When changes are made to the dataset, the changes in the database are actually done by the data adapter.

OleDbConnection is designed for connecting to a wide range of databases, like Microsoft Access and Oracle.

If you have any questions or suggestions about how to connect to access the database in vb.net, please leave a comment below.

Other Articles Readers might read:

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25+ Latest VB.Net Project Topics For Students [2024]

VB.Net, a versatile programming language, holds significant relevance in today’s tech-driven world. It is a powerful tool for developing various applications, from simple utilities to complex enterprise systems. Its user-friendly syntax and extensive framework make it an ideal choice for students looking to delve into the world of software development.

When it comes to learning VB.Net, practical application through project-based learning is invaluable. By working on projects, students can apply theoretical knowledge to real-world scenarios, thereby reinforcing their understanding and skills. 

Additionally, projects provide a hands-on learning experience that fosters creativity, problem-solving abilities, and critical thinking—all essential qualities for aspiring programmers.

In this blog, we aim to showcase the benefits of using project topics in VB.Net for students. We will explore a diverse range of VB.Net project topics suited for various skill levels, from beginners to advanced learners. Join us as we embark on this journey of learning and discovery in the world of VB.Net projects.

What is a VB.NET Project?

Table of Contents

A VB.NET project is a software development endeavor undertaken using the Visual Basic.NET programming language. It involves the creation of applications, utilities, or systems using the features and capabilities provided by VB.NET. 

Projects can range from simple desktop applications to more complex web applications or enterprise-level software solutions. VB.NET projects typically involve designing, coding, testing, and debugging software components to achieve specific functionalities or address particular needs. 

These projects serve as practical learning experiences for students and professionals, allowing them to apply VB.NET concepts and techniques in real-world scenarios.

Example of VB.NET Project

One example of a VB.NET project could be a simple inventory management system for a small business. This project would involve creating a desktop application using Visual Basic.NET that allows users to track inventory levels, add new items, remove items, and generate reports.

The project would include features such as a user-friendly interface for inputting and editing inventory data, validation to ensure data accuracy, and the ability to generate reports on inventory levels, sales trends, and stock shortages.

Additionally, the project might incorporate database integration to store and retrieve inventory data and functionality for exporting reports to various file formats such as Excel or PDF.

Overall, this VB.NET project provides a practical example of how the language can be used to develop functional business applications to streamline operations and improve efficiency.

Trending VB.Net Project Topics For Beginners to Advanced Level

Here’s a list of the best VB.NET project topics suitable for beginners to advanced-level developers:

Beginners Developers

1. Simple Calculator Application

Create a basic calculator application in VB.Net that performs arithmetic operations like addition, subtraction, multiplication, and division. This project will help beginners grasp fundamental concepts such as user input, event handling, and basic arithmetic operations in VB.Net.

2. To-Do List Manager

Develop a to-do list manager application that allows users to add, edit, delete, and mark tasks as completed. This project will introduce beginners to concepts such as data manipulation, user interface design, and handling user interactions using VB.Net.

3. Temperature Converter

Design a temperature converter application that converts temperatures between Celsius, Fahrenheit, and Kelvin scales. This project will familiarize beginners with variables, data types, conditional statements, and mathematical operations in VB.Net.

4. Student Grade Calculator

Build a student grade calculator application that calculates average grades, determines letter grades, and provides feedback based on input scores. This project will involve implementing loops, arrays, and conditional statements to handle multiple student records in VB.Net.

5. Simple Text Editor

Create a basic text editor application with features like text entry, editing, saving, and opening files. This project will introduce beginners to file handling, text manipulation, and basic GUI (Graphical User Interface) design using VB.Net.

6. Currency Converter  

Develop a currency converter application that converts currencies between different countries based on real-time exchange rates. This project will involve retrieving data from external APIs, parsing JSON/XML data, and displaying results in VB.Net.

7. BMI (Body Mass Index) Calculator

Design a BMI calculator application that calculates a person’s BMI based on their height and weight inputs. This project will teach beginners about mathematical formulas, input validation, and displaying results in VB.Net.

8. Quiz Application

Create a simple quiz application with multiple-choice questions on various topics. This project will involve designing a user interface for displaying questions, handling user responses, scoring, and providing feedback using VB.Net.

9. Library Management System

Develop a basic library management system that allows users to add, edit, delete, and search for books in a library database. This project will introduce beginners to database management, SQL queries, and CRUD (Create, Read, Update, Delete) operations in VB.Net.

Intermediate Devlopers

10. Inventory Management System

Design an inventory management system for a small business, allowing users to track stock levels, manage suppliers, generate reports, and automate reordering processes. This project involves database integration and advanced GUI design.

11. Expense Tracker

Develop an expense-tracking application that helps users record, categorize, and analyze their expenses over time. This project involves database management, data visualization, and advanced user input validation.

12. Banking System Simulation

Create a banking system simulation with features like account creation, funds transfer, balance inquiries, and transaction history. This project involves implementing object-oriented programming principles, encryption techniques, and robust error handling.

13. Hospital Management System

Build a hospital management system for managing patient records, scheduling appointments, tracking medical staff, and generating medical reports. This project involves database design, user authentication, and role-based access control.

14. Online Bookstore

Develop an online bookstore application where users can browse, search, purchase, and review books. This project involves web development using ASP.NET, database integration for managing book inventory and orders, and secure payment processing.

15. Employee Attendance System

Design an employee attendance tracking system that records employee clock-ins, clock-outs, absences, and overtime hours. This project involves real-time data processing, user authentication, and data visualization.

16. E-commerce Website

Create an e-commerce website where users can browse products, add items to their cart, checkout, and manage their orders. This project involves web development using ASP.NET MVC, database management, and integration with payment gateways.

17. Customer Relationship Management (CRM) System

Develop a CRM system for businesses to manage customer interactions, track leads, analyze sales data, and automate marketing campaigns. This project involves database design, data analytics, and integration with email marketing tools.

18. Online Auction System

Build an online auction platform where users can bid on items, monitor auctions, and manage their bids. This project involves real-time communication, bidding algorithms, secure payment processing, and user feedback mechanisms.

Advanced Developers

19. Social Media Analytics Dashboard

Develop a comprehensive analytics dashboard for social media platforms, allowing users to track engagement metrics, analyze trends, and generate reports. This project involves data aggregation from APIs, data visualization using advanced charting libraries, and predictive analytics algorithms.

20. Machine Learning-Based Stock Prediction

Create a stock prediction application using machine learning algorithms to forecast stock prices based on historical data. This project involves data preprocessing, feature engineering, model training, and deployment using VB.Net and ML.NET library.

21. Virtual Reality Simulation

Design a virtual reality simulation application for training purposes, such as flight simulation or medical procedures. This project involves integrating VR hardware, developing immersive environments, and implementing interactive simulations using VB.Net and Unity3D.

22. Automated Trading System

Build an automated trading system that executes buy/sell orders in financial markets based on predefined trading strategies. This project involves real-time market data processing, algorithmic trading strategies, and risk management techniques implemented in VB.Net.

23. Natural Language Processing (NLP) Chatbot

Develop a conversational chatbot capable of understanding and responding to natural language queries. This project involves training NLP models, integrating with language processing APIs, and implementing dialogue management logic using VB.Net and libraries like NLTK or spaCy.

24. Smart Home Automation System

Design a smart home automation system that enables users to control various home devices remotely through a centralized application. This project involves IoT integration, sensor data processing, and implementing automation rules using VB.Net and Arduino/Raspberry Pi.

25. Computer Vision-Based Object Recognition

Create an object recognition application using computer vision algorithms to detect and classify objects in images or videos. This project involves deep learning models, image processing techniques, and integration with the OpenCV library using VB.Net.

26. Blockchain-Based Voting System

Develop a secure and transparent voting system using blockchain technology to ensure the integrity and immutability of voting records. This project involves implementing smart contracts, distributed ledger technology, and cryptographic techniques in VB.Net and the Ethereum platform.

27. Healthcare Data Analysis Platform

Build a healthcare data analysis platform for medical professionals to analyze patient records, diagnose diseases, and predict treatment outcomes. This project involves data integration from healthcare databases, machine learning algorithms for predictive analytics, and HIPAA-compliant data management using VB.Net and Python libraries.

These project ideas should provide a good starting point for beginners and also challenge more advanced developers to explore deeper functionality and implementation details.

Advantages of using VB.NET Project Topics for Students

There are several advantages to using VB.NET project topics for students:

• User-Friendly Syntax: VB.NET offers a simple and intuitive syntax, making it easier for students to learn and understand programming concepts.
• Extensive Framework: Students can leverage the extensive .NET framework provided by VB.NET, allowing for rapid application development with built-in functionalities.
• Abundance of Resources: VB.NET has a vast community and ample online resources, including tutorials, forums, and documentation, providing valuable support for students during their learning journey.
• Seamless Integration: VB.NET seamlessly integrates with other Microsoft technologies like SQL Server, Azure, and Office applications, offering students a holistic understanding of software development.
• Career Opportunities: Proficiency in VB.NET opens doors to a wide range of career opportunities in software development, particularly in industries where Microsoft technologies are prevalent.

How to Make Setup of VB.NET Project

Creating a setup for a VB.NET project involves packaging your application along with any required dependencies and creating an installer that users can run to install your application on their systems. Here’s a step-by-step guide on how to create a setup for a VB.NET project using Visual Studio:

• Open your VB.NET project in Visual Studio.
• Navigate to the “Build” menu and select “Publish <YourProjectName>”.
• In the Publish Wizard, choose the publishing location, such as a folder, FTP server, or Azure App Service.
• Configure publishing options like deployment mode and updates.
• Click “Finish” to generate the deployment package.
• Distribute the generated setup files to users for installation.
• Optionally, create an installer using third-party tools like Inno Setup or WiX Toolset for a more customizable installation process.

By following these steps, you can create a setup for your VB.NET project and distribute it to users for installation on their systems.

Tips for Successful Implementation

Implementing VB.NET projects successfully requires careful planning, adherence to best practices, and effective project management. Here are some tips to ensure successful implementation:

Plan Thoroughly

Clearly define project requirements, objectives, and scope before starting development.

Follow Best Practices

Adhere to coding standards, use meaningful variable names, and organize your code logically.

Use Version Control

Utilize version control systems like Git to manage code changes and collaborate effectively.

Test Rigorously

Conduct thorough testing at each stage of development to catch bugs early and ensure software reliability.

Document Extensively

Document code, design decisions, and project processes to facilitate maintenance and future enhancements.

Seek Feedback

Solicit feedback from stakeholders and end-users throughout the development process to ensure alignment with requirements and expectations.

By following these tips, you can increase the likelihood of success in implementing VB.NET projects delivering high-quality software solutions that meet stakeholders’ requirements and expectations.

Final Thoughts

VB.NET project topics offer an invaluable opportunity for students to enhance their programming skills and explore the diverse applications of the Visual Basic.NET language. 

From beginner-level projects focusing on fundamental concepts to advanced endeavors incorporating cutting-edge technologies, the realm of VB.NET projects is vast and enriching. By undertaking these projects, students not only solidify their understanding of programming principles but also develop problem-solving abilities and creativity. 

Whether it’s building simple utilities or complex enterprise systems, the journey of exploring VB.NET project topics is both educational and rewarding, paving the way for future success in software development endeavors.

1. How do I choose the right VB.Net project topic?

Consider your interests, skill level, and career goals when selecting a project topic. Choose something that challenges you but is also achievable within your capabilities.

2. Can I use VB.NET for web development?

Yes, VB.NET can be used for web development through ASP.NET, a web application framework developed by Microsoft. ASP.NET allows developers to build dynamic web applications using VB.NET for server-side programming, HTML/CSS for front-end design, and SQL Server for database integration.

3. How can I get started with VB.NET projects if I’m new to programming?

To begin with VB.NET projects, it’s advisable to start with simple projects like a calculator or to-do list manager. Utilize online resources such as tutorials, forums, and documentation to learn the basics of VB.NET programming. Practice regularly and gradually tackle more complex projects as you gain confidence and proficiency in the language.

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Open SQL Server database by using SQL Server .NET Data Provider with Visual Basic .NET

• 3 contributors

This article provides information about how to open SQL Server databases by using SQL Server .NET Data Provider with Visual Basic .NET.

Original product version:   Visual Basic .NET Original KB number:   308656

This article describes how you can use ADO.NET to open a SQL Server database by using the SQL Server .NET data provider. ADO.NET gathers all of the classes that are required for data handling. The System.Data.SqlClient namespace describes a collection of classes that are used to programmatically access a SQL Server data source. You can access ADO classes through the System.Data.OleDb namespace to provide support for OLE DB databases.

In this article, connections are set up both programmatically and using the Visual Studio .NET Server Explorer. The code samples in this article use the SqlConnection , SqlCommand , and SqlDataReader ADO.NET objects.

Requirements

The following list outlines the required hardware, software, network infrastructure, and service packs that you need:

• Microsoft SQL Server
• Visual Basic .NET

SQL Server and Visual Basic .NET must be installed and running on the same computer. In addition, the user must be able to use Windows Integrated Security to connect to SQL Server.

This article assumes that you're familiar with the following topics:

• ADO.NET concepts
• SQL Server concepts and Transact-SQL (T-SQL) syntax
• Northwind sample database

Create Visual Basic .NET Windows application

Start Visual Studio .NET, and create a new Visual Basic Windows Application project named SQLDataAccess .

Open Form1. In the first line of Form1.vb , add a reference to the ADO.NET namespace as follows:

From the Windows Start menu, point to Programs , point to Microsoft SQL Server, and then click SQL Server Service Manager to ensure that the SQL Server service is running on your computer.

Set the Server property to the name of your computer, and then set the Services property to MSSQLServer .

If the service isn't running, click Start .

Close the SQL Server Service Manager dialog box.

Create ADO.NET objects

Modify the Form1 class as follows:

The SqlConnection object establishes a database connection, the SqlCommand object runs a query against the database, and the SqlDataReader object retrieves the results of the query.

Use the SqlConnection object to open SQL Server connection

To set up the connection string of the SqlConnection object, add the following code to the Form1_Load event procedure:

To set up the Command object, which contains the SQL query, add the following code to the Form1_Load event procedure:

SqlConnection uses your Windows logon details to connect to the Northwind database on your computer.

Use the SqlDataReader object to retrieve data from SQL Server

Add the following code to the Form1_Load event procedure:

When the myCmd.ExecuteReader method is executed, SqlCommand retrieves two fields from the Employees table and creates a SqlDataReader object.

To display the query results, add the following code to the Form1_Load event procedure:

The myReader.Read method returns a boolean value, which indicates whether there are more records to be read. The results of the SQL query are displayed in a message box.

To close the SqlDataReader and SqlConnection objects, add the following code to the Form1_Load event procedure:

Save and run the project.

View database in Server Explorer

• On the View menu, click Server Explorer.
• Right-click Data Connections , and then click Add connection .
• In the Data Link Properties dialog box, click localhost in the Select or enter a server name box.
• Click Windows NT Integrated Security to log on to the server.
• Click Select the database on the server , and then select Northwind database from the list.
• Click Test Connection to validate the connection, and then click OK .
• In the Server Explorer, click to expand the Data Connections tree so that the Employees table node expands. The properties of individual fields appear in the Properties window.

Use Server Explorer to open SQL Server connection

View Form1 in Design view.

Drag the FirstName and LastName database fields from Employees table in Server Explorer, and drop these fields onto Form1. A SqlConnection and SqlDataAdapter object are created on the form.

From the View menu, click Toolbox .

On the Data tab, drag a DataSet object (DataSet1), and drop it onto the form.

In the Add Dataset dialog box, click Untyped dataset , and then click OK .

Insert a line of code before the DataReader and Connection objects are closed in the Form1_Load event procedure. The end of the procedure should appear as follows:

On the Window Forms tab of the toolbox, drag a DataGrid control, and drop it onto Form1.

To bind the DataGrid to the DataSet object that you created earlier, add the following code to the Form1_Load event procedure before the myReader.close() line of code:

For more information about using ADO.NET, refer to the Data section of the Visual Basic topic in the Visual Studio .NET Help documentation.

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Creating an array of student names and scores in Visual Basic that updates a list box with the information

I am working on a project that has multiple forms. The main form has a listBox that displays the contents of a tab delimited text file. The text file looks like this:

Bowser, William C 84 98 77 83 75 92 Smithson, Anne K 76 87 65 Brewer, Juliette 23 Oblonski, Walter H 88 97 86 75 93 98 Smith, John D 86 75 84 93 91 78 Katinga, Raphael P 56 87 44 32 22 Robertson, Gerald T 67 78 87 93 87 75 Smith, John B 89 67 75 84 92 83

The assignment is as follows:

StudentScores Develop an application that reads in student names (limited to 20 students) and scores (up to 6 per student) from a tab delimited file, StudentScores.txt (in Student Files). The application shall allow the user to add students to the student set, add and change scores for a student in the student set, delete a student and the student’s scores from the student set, and save the student set back to the StudentScores.txt file.

I am not having any luck getting it to correctly add a new student & scores or save the current "updated" information. I think I am not using my arrays correctly. below is my code for the main form (frmStudentScores) and a second form (frmAddNewStudent)

My frmStudentScores code:

The code for form frmAddNewStudent (used to add a new student) is:

Also I have a Module with the name and scores arrays in it:

• 1 Parallel arrays are a horrible choice for this type of task –  OneFineDay Commented Dec 11, 2014 at 5:06
• Thats what I was told but the assignment specifically ask for parallel arrays. How would you advise me to do it if I were not using the parallel arrays? I am more interested in making it work than I am about using parallel arrays. –  Chip Datamaker Commented Dec 11, 2014 at 5:09
• 1 Ask your teacher if this would be acceptable in the work place, the answer would be no. There is a place for arrays and this is not it. Some day schools are going to have to step up and change there stupid curriculum. –  OneFineDay Commented Dec 11, 2014 at 5:11
• Arrays need to be ReDim before adding, all arrays must be dimension-ed the same if they are to be used by the same index. –  OneFineDay Commented Dec 11, 2014 at 5:15
• Do you think a Jagged Array would work better here? –  Chip Datamaker Commented Dec 11, 2014 at 5:20

Example of a custom class:

Get a students average grade(lambda expression):

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• VB.Net Basic Tutorial
• VB.Net - Home

VB.Net - Overview

Vb.net - environment setup, vb.net - program structure, vb.net - basic syntax, vb.net - data types, vb.net - variables.

• VB.Net - Constants

VB.Net - Modifiers

Vb.net - statements, vb.net - directives, vb.net - operators, vb.net - decision making, vb.net - loops, vb.net - strings, vb.net - date & time, vb.net - arrays, vb.net - collections, vb.net - functions.

• VB.Net - Subs

VB.Net - Classes & Objects

Vb.net - exception handling, vb.net - file handling, vb.net - basic controls, vb.net - dialog boxes.

• VB.Net - Advanced Forms

VB.Net - Event Handling

• VB.Net Advanced Tutorial

VB.Net - Regular Expressions

Vb.net - database access, vb.net - excel sheet, vb.net - send email, vb.net - xml processing, vb.net - web programming.

• VB.Net Useful Resources

VB.Net - Quick Guide

• VB.Net - Useful Resources
• VB.Net - Discussion
• Selected Reading
• UPSC IAS Exams Notes
• Developer's Best Practices
• Questions and Answers
• Effective Resume Writing
• HR Interview Questions
• Computer Glossary

Visual Basic .NET (VB.NET) is an object-oriented computer programming language implemented on the .NET Framework. Although it is an evolution of classic Visual Basic language, it is not backwards-compatible with VB6, and any code written in the old version does not compile under VB.NET.

Like all other .NET languages, VB.NET has complete support for object-oriented concepts. Everything in VB.NET is an object, including all of the primitive types (Short, Integer, Long, String, Boolean, etc.) and user-defined types, events, and even assemblies. All objects inherits from the base class Object.

VB.NET is implemented by Microsoft's .NET framework. Therefore, it has full access to all the libraries in the .Net Framework. It's also possible to run VB.NET programs on Mono, the open-source alternative to .NET, not only under Windows, but even Linux or Mac OSX.

The following reasons make VB.Net a widely used professional language −

Modern, general purpose.

Object oriented.

Component oriented.

Easy to learn.

Structured language.

It produces efficient programs.

It can be compiled on a variety of computer platforms.

Part of .Net Framework.

Strong Programming Features VB.Net

VB.Net has numerous strong programming features that make it endearing to multitude of programmers worldwide. Let us mention some of these features −

Boolean Conditions

Automatic Garbage Collection

Standard Library

Assembly Versioning

Properties and Events

Delegates and Events Management

Easy-to-use Generics

Conditional Compilation

Simple Multithreading

In this chapter, we will discuss the tools available for creating VB.Net applications.

We have already mentioned that VB.Net is part of .Net framework and used for writing .Net applications. Therefore before discussing the available tools for running a VB.Net program, let us understand how VB.Net relates to the .Net framework.

The .Net Framework

The .Net framework is a revolutionary platform that helps you to write the following types of applications −

Windows applications

Web applications

Web services

The .Net framework applications are multi-platform applications. The framework has been designed in such a way that it can be used from any of the following languages: Visual Basic, C#, C++, Jscript, and COBOL, etc.

All these languages can access the framework as well as communicate with each other.

The .Net framework consists of an enormous library of codes used by the client languages like VB.Net. These languages use object-oriented methodology.

Following are some of the components of the .Net framework −

Common Language Runtime (CLR)

The .Net Framework Class Library

Common Language Specification

Common Type System

Metadata and Assemblies

Windows Forms

ASP.Net and ASP.Net AJAX

Windows Workflow Foundation (WF)

Windows Presentation Foundation

Windows Communication Foundation (WCF)

For the jobs each of these components perform, please see ASP.Net - Introduction , and for details of each component, please consult Microsoft's documentation.

Integrated Development Environment (IDE) For VB.Net

Microsoft provides the following development tools for VB.Net programming −

Visual Studio 2010 (VS)

Visual Basic 2010 Express (VBE)

Visual Web Developer

The last two are free. Using these tools, you can write all kinds of VB.Net programs from simple command-line applications to more complex applications. Visual Basic Express and Visual Web Developer Express edition are trimmed down versions of Visual Studio and has the same look and feel. They retain most features of Visual Studio. In this tutorial, we have used Visual Basic 2010 Express and Visual Web Developer (for the web programming chapter).

You can download it from here . It gets automatically installed in your machine. Please note that you need an active internet connection for installing the express edition.

Writing VB.Net Programs on Linux or Mac OS

Although the.NET Framework runs on the Windows operating system, there are some alternative versions that work on other operating systems. Mono is an open-source version of the .NET Framework which includes a Visual Basic compiler and runs on several operating systems, including various flavors of Linux and Mac OS. The most recent version is VB 2012.

The stated purpose of Mono is not only to be able to run Microsoft .NET applications cross-platform, but also to bring better development tools to Linux developers. Mono can be run on many operating systems including Android, BSD, iOS, Linux, OS X, Windows, Solaris and UNIX.

Before we study basic building blocks of the VB.Net programming language, let us look a bare minimum VB.Net program structure so that we can take it as a reference in upcoming chapters.

VB.Net Hello World Example

A VB.Net program basically consists of the following parts −

Namespace declaration

A class or module

One or more procedures

The Main procedure

Statements & Expressions

Let us look at a simple code that would print the words "Hello World" −

When the above code is compiled and executed, it produces the following result −

Let us look various parts of the above program −

The first line of the program Imports System is used to include the System namespace in the program.

The next line has a Module declaration, the module Module1 . VB.Net is completely object oriented, so every program must contain a module of a class that contains the data and procedures that your program uses.

Classes or Modules generally would contain more than one procedure. Procedures contain the executable code, or in other words, they define the behavior of the class. A procedure could be any of the following −

RemoveHandler

The next line( 'This program) will be ignored by the compiler and it has been put to add additional comments in the program.

The next line defines the Main procedure, which is the entry point for all VB.Net programs. The Main procedure states what the module or class will do when executed.

The Main procedure specifies its behavior with the statement

Console.WriteLine("Hello World") WriteLine is a method of the Console class defined in the System namespace. This statement causes the message "Hello, World!" to be displayed on the screen.

The last line Console.ReadKey() is for the VS.NET Users. This will prevent the screen from running and closing quickly when the program is launched from Visual Studio .NET.

Compile & Execute VB.Net Program

If you are using Visual Studio.Net IDE, take the following steps −

Start Visual Studio.

On the menu bar, choose File → New → Project.

Choose Visual Basic from templates

Choose Console Application.

Specify a name and location for your project using the Browse button, and then choose the OK button.

The new project appears in Solution Explorer.

Write code in the Code Editor.

Click the Run button or the F5 key to run the project. A Command Prompt window appears that contains the line Hello World.

You can compile a VB.Net program by using the command line instead of the Visual Studio IDE −

Open a text editor and add the above mentioned code.

Save the file as helloworld.vb

Open the command prompt tool and go to the directory where you saved the file.

Type vbc helloworld.vb and press enter to compile your code.

If there are no errors in your code the command prompt will take you to the next line and would generate helloworld.exe executable file.

Next, type helloworld to execute your program.

You will be able to see "Hello World" printed on the screen.

VB.Net is an object-oriented programming language. In Object-Oriented Programming methodology, a program consists of various objects that interact with each other by means of actions. The actions that an object may take are called methods. Objects of the same kind are said to have the same type or, more often, are said to be in the same class.

When we consider a VB.Net program, it can be defined as a collection of objects that communicate via invoking each other's methods. Let us now briefly look into what do class, object, methods and instance variables mean.

Object − Objects have states and behaviors. Example: A dog has states - color, name, breed as well as behaviors - wagging, barking, eating, etc. An object is an instance of a class.

Class − A class can be defined as a template/blueprint that describes the behaviors/states that objects of its type support.

Methods − A method is basically a behavior. A class can contain many methods. It is in methods where the logics are written, data is manipulated and all the actions are executed.

Instance Variables − Each object has its unique set of instance variables. An object's state is created by the values assigned to these instance variables.

A Rectangle Class in VB.Net

For example, let us consider a Rectangle object. It has attributes like length and width. Depending upon the design, it may need ways for accepting the values of these attributes, calculating area and displaying details.

Let us look at an implementation of a Rectangle class and discuss VB.Net basic syntax on the basis of our observations in it −

In previous chapter, we created a Visual Basic module that held the code. Sub Main indicates the entry point of VB.Net program. Here, we are using Class that contains both code and data. You use classes to create objects. For example, in the code, r is a Rectangle object.

An object is an instance of a class −

A class may have members that can be accessible from outside class, if so specified. Data members are called fields and procedure members are called methods.

Shared methods or static methods can be invoked without creating an object of the class. Instance methods are invoked through an object of the class −

Identifiers

An identifier is a name used to identify a class, variable, function, or any other user-defined item. The basic rules for naming classes in VB.Net are as follows −

A name must begin with a letter that could be followed by a sequence of letters, digits (0 - 9) or underscore. The first character in an identifier cannot be a digit.

It must not contain any embedded space or symbol like ? - +! @ # % ^ & * ( ) [ ] { } . ; : " ' / and \. However, an underscore ( _ ) can be used.

It should not be a reserved keyword.

VB.Net Keywords

The following table lists the VB.Net reserved keywords −

Data types refer to an extensive system used for declaring variables or functions of different types. The type of a variable determines how much space it occupies in storage and how the bit pattern stored is interpreted.

Data Types Available in VB.Net

VB.Net provides a wide range of data types. The following table shows all the data types available −

The following example demonstrates use of some of the types −

The Type Conversion Functions in VB.Net

VB.Net provides the following in-line type conversion functions −

The following example demonstrates some of these functions −

A variable is nothing but a name given to a storage area that our programs can manipulate. Each variable in VB.Net has a specific type, which determines the size and layout of the variable's memory; the range of values that can be stored within that memory; and the set of operations that can be applied to the variable.

We have already discussed various data types. The basic value types provided in VB.Net can be categorized as −

VB.Net also allows defining other value types of variable like Enum and reference types of variables like Class . We will discuss date types and Classes in subsequent chapters.

Variable Declaration in VB.Net

The Dim statement is used for variable declaration and storage allocation for one or more variables. The Dim statement is used at module, class, structure, procedure or block level.

Syntax for variable declaration in VB.Net is −

attributelist is a list of attributes that apply to the variable. Optional.

accessmodifier defines the access levels of the variables, it has values as - Public, Protected, Friend, Protected Friend and Private. Optional.

Shared declares a shared variable, which is not associated with any specific instance of a class or structure, rather available to all the instances of the class or structure. Optional.

Shadows indicate that the variable re-declares and hides an identically named element, or set of overloaded elements, in a base class. Optional.

Static indicates that the variable will retain its value, even when the after termination of the procedure in which it is declared. Optional.

ReadOnly means the variable can be read, but not written. Optional.

WithEvents specifies that the variable is used to respond to events raised by the instance assigned to the variable. Optional.

Variablelist provides the list of variables declared.

Each variable in the variable list has the following syntax and parts −

variablename − is the name of the variable

boundslist − optional. It provides list of bounds of each dimension of an array variable.

New − optional. It creates a new instance of the class when the Dim statement runs.

datatype − Required if Option Strict is On. It specifies the data type of the variable.

initializer − Optional if New is not specified. Expression that is evaluated and assigned to the variable when it is created.

Some valid variable declarations along with their definition are shown here −

Variable Initialization in VB.Net

Variables are initialized (assigned a value) with an equal sign followed by a constant expression. The general form of initialization is −

for example,

You can initialize a variable at the time of declaration as follows −

Try the following example which makes use of various types of variables −

Accepting Values from User

The Console class in the System namespace provides a function ReadLine for accepting input from the user and store it into a variable. For example,

The following example demonstrates it −

When the above code is compiled and executed, it produces the following result (assume the user inputs Hello World) −

Lvalues and Rvalues

There are two kinds of expressions −

lvalue − An expression that is an lvalue may appear as either the left-hand or right-hand side of an assignment.

rvalue − An expression that is an rvalue may appear on the right- but not left-hand side of an assignment.

Variables are lvalues and so may appear on the left-hand side of an assignment. Numeric literals are rvalues and so may not be assigned and can not appear on the left-hand side. Following is a valid statement −

But following is not a valid statement and would generate compile-time error −

VB.Net - Constants and Enumerations

The constants refer to fixed values that the program may not alter during its execution. These fixed values are also called literals.

Constants can be of any of the basic data types like an integer constant, a floating constant, a character constant, or a string literal. There are also enumeration constants as well.

The constants are treated just like regular variables except that their values cannot be modified after their definition.

An enumeration is a set of named integer constants.

Declaring Constants

In VB.Net, constants are declared using the Const statement. The Const statement is used at module, class, structure, procedure, or block level for use in place of literal values.

The syntax for the Const statement is −

attributelist − specifies the list of attributes applied to the constants; you can provide multiple attributes separated by commas. Optional.

accessmodifier − specifies which code can access these constants. Optional. Values can be either of the: Public, Protected, Friend, Protected Friend, or Private.

Shadows − this makes the constant hide a programming element of identical name in a base class. Optional.

Constantlist − gives the list of names of constants declared. Required.

Where, each constant name has the following syntax and parts −

constantname − specifies the name of the constant

datatype − specifies the data type of the constant

initializer − specifies the value assigned to the constant

For example,

The following example demonstrates declaration and use of a constant value −

Print and Display Constants in VB.Net

VB.Net provides the following print and display constants −

Declaring Enumerations

An enumerated type is declared using the Enum statement. The Enum statement declares an enumeration and defines the values of its members. The Enum statement can be used at the module, class, structure, procedure, or block level.

The syntax for the Enum statement is as follows −

attributelist − refers to the list of attributes applied to the variable. Optional.

accessmodifier − specifies which code can access these enumerations. Optional. Values can be either of the: Public, Protected, Friend or Private.

Shadows − this makes the enumeration hide a programming element of identical name in a base class. Optional.

enumerationname − name of the enumeration. Required

datatype − specifies the data type of the enumeration and all its members.

memberlist − specifies the list of member constants being declared in this statement. Required.

Each member in the memberlist has the following syntax and parts:

name − specifies the name of the member. Required.

initializer − value assigned to the enumeration member. Optional.

The following example demonstrates declaration and use of the Enum variable Colors −

The modifiers are keywords added with any programming element to give some especial emphasis on how the programming element will behave or will be accessed in the program.

For example, the access modifiers: Public, Private, Protected, Friend, Protected Friend, etc., indicate the access level of a programming element like a variable, constant, enumeration or a class.

List of Available Modifiers in VB.Net

The following table provides the complete list of VB.Net modifiers −

A statement is a complete instruction in Visual Basic programs. It may contain keywords, operators, variables, literal values, constants and expressions.

Statements could be categorized as −

Declaration statements − these are the statements where you name a variable, constant, or procedure, and can also specify a data type.

Executable statements − these are the statements, which initiate actions. These statements can call a method or function, loop or branch through blocks of code or assign values or expression to a variable or constant. In the last case, it is called an Assignment statement.

Declaration Statements

The declaration statements are used to name and define procedures, variables, properties, arrays, and constants. When you declare a programming element, you can also define its data type, access level, and scope.

The programming elements you may declare include variables, constants, enumerations, classes, structures, modules, interfaces, procedures, procedure parameters, function returns, external procedure references, operators, properties, events, and delegates.

Following are the declaration statements in VB.Net −

Executable Statements

An executable statement performs an action. Statements calling a procedure, branching to another place in the code, looping through several statements, or evaluating an expression are executable statements. An assignment statement is a special case of an executable statement.

The following example demonstrates a decision making statement −

The VB.Net compiler directives give instructions to the compiler to preprocess the information before actual compilation starts. All these directives begin with #, and only white-space characters may appear before a directive on a line. These directives are not statements.

VB.Net compiler does not have a separate preprocessor; however, the directives are processed as if there was one. In VB.Net, the compiler directives are used to help in conditional compilation. Unlike C and C++ directives, they are not used to create macros.

Compiler Directives in VB.Net

VB.Net provides the following set of compiler directives −

The #Const Directive

The #externalsource directive, the #if...then...#else directives, the #region directive.

This directive defines conditional compiler constants. Syntax for this directive is −

constname − specifies the name of the constant. Required.

expression − it is either a literal, or other conditional compiler constant, or a combination including any or all arithmetic or logical operators except Is .

The following code demonstrates a hypothetical use of the directive −

This directive is used for indicating a mapping between specific lines of source code and text external to the source. It is used only by the compiler and the debugger has no effect on code compilation.

This directive allows including external code from an external code file into a source code file.

Syntax for this directive is −

The parameters of #ExternalSource directive are the path of external file, line number of the first line, and the line where the error occurred.

This directive conditionally compiles selected blocks of Visual Basic code.

This directive helps in collapsing and hiding sections of code in Visual Basic files.

An operator is a symbol that tells the compiler to perform specific mathematical or logical manipulations. VB.Net is rich in built-in operators and provides following types of commonly used operators −

Arithmetic Operators

Comparison operators, logical/bitwise operators, bit shift operators, assignment operators, miscellaneous operators.

This tutorial will explain the most commonly used operators.

Following table shows all the arithmetic operators supported by VB.Net. Assume variable A holds 2 and variable B holds 7, then −

Show Examples

Following table shows all the comparison operators supported by VB.Net. Assume variable A holds 10 and variable B holds 20, then −

Apart from the above, VB.Net provides three more comparison operators, which we will be using in forthcoming chapters; however, we give a brief description here.

Is Operator − It compares two object reference variables and determines if two object references refer to the same object without performing value comparisons. If object1 and object2 both refer to the exact same object instance, result is True ; otherwise, result is False.

IsNot Operator − It also compares two object reference variables and determines if two object references refer to different objects. If object1 and object2 both refer to the exact same object instance, result is False ; otherwise, result is True.

Like Operator − It compares a string against a pattern.

Following table shows all the logical operators supported by VB.Net. Assume variable A holds Boolean value True and variable B holds Boolean value False, then −

We have already discussed the bitwise operators. The bit shift operators perform the shift operations on binary values. Before coming into the bit shift operators, let us understand the bit operations.

Bitwise operators work on bits and perform bit-by-bit operations. The truth tables for &, |, and ^ are as follows −

Assume if A = 60; and B = 13; now in binary format they will be as follows −

A = 0011 1100

B = 0000 1101

-----------------

A&B = 0000 1100

A|B = 0011 1101

A^B = 0011 0001

~A  = 1100 0011

We have seen that the Bitwise operators supported by VB.Net are And, Or, Xor and Not. The Bit shift operators are >> and << for left shift and right shift, respectively.

Assume that the variable A holds 60 and variable B holds 13, then −

There are following assignment operators supported by VB.Net −

There are few other important operators supported by VB.Net.

Operators Precedence in VB.Net

Operator precedence determines the grouping of terms in an expression. This affects how an expression is evaluated. Certain operators have higher precedence than others; for example, the multiplication operator has higher precedence than the addition operator −

For example, x = 7 + 3 * 2; here, x is assigned 13, not 20 because operator * has higher precedence than +, so it first gets multiplied with 3*2 and then adds into 7.

Here, operators with the highest precedence appear at the top of the table, those with the lowest appear at the bottom. Within an expression, higher precedence operators will be evaluated first.

Decision making structures require that the programmer specify one or more conditions to be evaluated or tested by the program, along with a statement or statements to be executed if the condition is determined to be true, and optionally, other statements to be executed if the condition is determined to be false.

Following is the general form of a typical decision making structure found in most of the programming languages −

VB.Net provides the following types of decision making statements. Click the following links to check their details.

There may be a situation when you need to execute a block of code several number of times. In general, statements are executed sequentially: The first statement in a function is executed first, followed by the second, and so on.

Programming languages provide various control structures that allow for more complicated execution paths.

A loop statement allows us to execute a statement or group of statements multiple times and following is the general form of a loop statement in most of the programming languages −

VB.Net provides following types of loops to handle looping requirements. Click the following links to check their details.

Loop Control Statements

Loop control statements change execution from its normal sequence. When execution leaves a scope, all automatic objects that were created in that scope are destroyed.

VB.Net provides the following control statements. Click the following links to check their details.

In VB.Net, you can use strings as array of characters, however, more common practice is to use the String keyword to declare a string variable. The string keyword is an alias for the System.String class.

Creating a String Object

You can create string object using one of the following methods −

By assigning a string literal to a String variable

By using a String class constructor

By using the string concatenation operator (+)

By retrieving a property or calling a method that returns a string

By calling a formatting method to convert a value or object to its string representation

The following example demonstrates this −

Properties of the String Class

The String class has the following two properties −

Methods of the String Class

The String class has numerous methods that help you in working with the string objects. The following table provides some of the most commonly used methods −

The above list of methods is not exhaustive, please visit MSDN library for the complete list of methods and String class constructors.

The following example demonstrates some of the methods mentioned above −

Comparing Strings

String Contains String

Getting a Substring:

Joining Strings

Most of the softwares you write need implementing some form of date functions returning current date and time. Dates are so much part of everyday life that it becomes easy to work with them without thinking. VB.Net also provides powerful tools for date arithmetic that makes manipulating dates easy.

The Date data type contains date values, time values, or date and time values. The default value of Date is 0:00:00 (midnight) on January 1, 0001. The equivalent .NET data type is System.DateTime .

The DateTime structure represents an instant in time, typically expressed as a date and time of day

You can also get the current date and time from the DateAndTime class.

The DateAndTime module contains the procedures and properties used in date and time operations.

Properties and Methods of the DateTime Structure

The following table lists some of the commonly used properties of the DateTime Structure −

The following table lists some of the commonly used methods of the DateTime structure −

The above list of methods is not exhaustive, please visit Microsoft documentation for the complete list of methods and properties of the DateTime structure.

Creating a DateTime Object

You can create a DateTime object in one of the following ways −

By calling a DateTime constructor from any of the overloaded DateTime constructors.

By assigning the DateTime object a date and time value returned by a property or method.

By parsing the string representation of a date and time value.

By calling the DateTime structure's implicit default constructor.

When the above code was compiled and executed, it produces the following result −

Getting the Current Date and Time

The following programs demonstrate how to get the current date and time in VB.Net −

Current Time −

Current Date −

Formatting Date

A Date literal should be enclosed within hash signs (# #), and specified in the format M/d/yyyy, for example #12/16/2012#. Otherwise, your code may change depending on the locale in which your application is running.

For example, you specified Date literal of #2/6/2012# for the date February 6, 2012. It is alright for the locale that uses mm/dd/yyyy format. However, in a locale that uses dd/mm/yyyy format, your literal would compile to June 2, 2012. If a locale uses another format say, yyyy/mm/dd, the literal would be invalid and cause a compiler error.

To convert a Date literal to the format of your locale or to a custom format, use the Format function of String class, specifying either a predefined or user-defined date format.

The following example demonstrates this.

Predefined Date/Time Formats

The following table identifies the predefined date and time format names. These may be used by name as the style argument for the Format function −

For other formats like user-defined formats, please consult Microsoft Documentation .

Properties and Methods of the DateAndTime Class

The following table lists some of the commonly used properties of the DateAndTime Class −

The following table lists some of the commonly used methods of the DateAndTime class −

The above list is not exhaustive. For complete list of properties and methods of the DateAndTime class, please consult Microsoft Documentation .

The following program demonstrates some of these and methods −

An array stores a fixed-size sequential collection of elements of the same type. An array is used to store a collection of data, but it is often more useful to think of an array as a collection of variables of the same type.

All arrays consist of contiguous memory locations. The lowest address corresponds to the first element and the highest address to the last element.

Creating Arrays in VB.Net

To declare an array in VB.Net, you use the Dim statement. For example,

You can also initialize the array elements while declaring the array. For example,

The elements in an array can be stored and accessed by using the index of the array. The following program demonstrates this −

Dynamic Arrays

Dynamic arrays are arrays that can be dimensioned and re-dimensioned as par the need of the program. You can declare a dynamic array using the ReDim statement.

Syntax for ReDim statement −

The Preserve keyword helps to preserve the data in an existing array, when you resize it.

arrayname is the name of the array to re-dimension.

subscripts specifies the new dimension.

Multi-Dimensional Arrays

VB.Net allows multidimensional arrays. Multidimensional arrays are also called rectangular arrays.

You can declare a 2-dimensional array of strings as −

or, a 3-dimensional array of Integer variables −

The following program demonstrates creating and using a 2-dimensional array −

Jagged Array

A Jagged array is an array of arrays. The following code shows declaring a jagged array named scores of Integers −

The following example illustrates using a jagged array −

The Array Class

The Array class is the base class for all the arrays in VB.Net. It is defined in the System namespace. The Array class provides various properties and methods to work with arrays.

Properties of the Array Class

The following table provides some of the most commonly used properties of the Array class −

Methods of the Array Class

The following table provides some of the most commonly used methods of the Array class −

For complete list of Array class properties and methods, please consult Microsoft documentation.

The following program demonstrates use of some of the methods of the Array class:

Collection classes are specialized classes for data storage and retrieval. These classes provide support for stacks, queues, lists, and hash tables. Most collection classes implement the same interfaces.

Collection classes serve various purposes, such as allocating memory dynamically to elements and accessing a list of items on the basis of an index, etc. These classes create collections of objects of the Object class, which is the base class for all data types in VB.Net.

Various Collection Classes and Their Usage

The following are the various commonly used classes of the System.Collection namespace. Click the following links to check their details.

A procedure is a group of statements that together perform a task when called. After the procedure is executed, the control returns to the statement calling the procedure. VB.Net has two types of procedures −

Sub procedures or Subs

Functions return a value, whereas Subs do not return a value.

Defining a Function

The Function statement is used to declare the name, parameter and the body of a function. The syntax for the Function statement is −

Modifiers − specify the access level of the function; possible values are: Public, Private, Protected, Friend, Protected Friend and information regarding overloading, overriding, sharing, and shadowing.

FunctionName − indicates the name of the function

ParameterList − specifies the list of the parameters

ReturnType − specifies the data type of the variable the function returns

Following code snippet shows a function FindMax that takes two integer values and returns the larger of the two.

Function Returning a Value

In VB.Net, a function can return a value to the calling code in two ways −

By using the return statement

By assigning the value to the function name

The following example demonstrates using the FindMax function −

Recursive Function

A function can call itself. This is known as recursion. Following is an example that calculates factorial for a given number using a recursive function −

Param Arrays

At times, while declaring a function or sub procedure, you are not sure of the number of arguments passed as a parameter. VB.Net param arrays (or parameter arrays) come into help at these times.

Passing Arrays as Function Arguments

You can pass an array as a function argument in VB.Net. The following example demonstrates this −

VB.Net - Sub Procedures

As we mentioned in the previous chapter, Sub procedures are procedures that do not return any value. We have been using the Sub procedure Main in all our examples. We have been writing console applications so far in these tutorials. When these applications start, the control goes to the Main Sub procedure, and it in turn, runs any other statements constituting the body of the program.

Defining Sub Procedures

The Sub statement is used to declare the name, parameter and the body of a sub procedure. The syntax for the Sub statement is −

Modifiers − specify the access level of the procedure; possible values are - Public, Private, Protected, Friend, Protected Friend and information regarding overloading, overriding, sharing, and shadowing.

SubName − indicates the name of the Sub

The following example demonstrates a Sub procedure CalculatePay that takes two parameters hours and wages and displays the total pay of an employee −

Passing Parameters by Value

This is the default mechanism for passing parameters to a method. In this mechanism, when a method is called, a new storage location is created for each value parameter. The values of the actual parameters are copied into them. So, the changes made to the parameter inside the method have no effect on the argument.

In VB.Net, you declare the reference parameters using the ByVal keyword. The following example demonstrates the concept −

It shows that there is no change in the values though they had been changed inside the function.

Passing Parameters by Reference

A reference parameter is a reference to a memory location of a variable. When you pass parameters by reference, unlike value parameters, a new storage location is not created for these parameters. The reference parameters represent the same memory location as the actual parameters that are supplied to the method.

In VB.Net, you declare the reference parameters using the ByRef keyword. The following example demonstrates this −

When you define a class, you define a blueprint for a data type. This doesn't actually define any data, but it does define what the class name means, that is, what an object of the class will consist of and what operations can be performed on such an object.

Objects are instances of a class. The methods and variables that constitute a class are called members of the class.

Class Definition

A class definition starts with the keyword Class followed by the class name; and the class body, ended by the End Class statement. Following is the general form of a class definition −

attributelist is a list of attributes that apply to the class. Optional.

accessmodifier defines the access levels of the class, it has values as - Public, Protected, Friend, Protected Friend and Private. Optional.

MustInherit specifies that the class can be used only as a base class and that you cannot create an object directly from it, i.e., an abstract class. Optional.

NotInheritable specifies that the class cannot be used as a base class.

Partial indicates a partial definition of the class.

Inherits specifies the base class it is inheriting from.

Implements specifies the interfaces the class is inheriting from.

The following example demonstrates a Box class, with three data members, length, breadth and height −

Member Functions and Encapsulation

A member function of a class is a function that has its definition or its prototype within the class definition like any other variable. It operates on any object of the class of which it is a member and has access to all the members of a class for that object.

Member variables are attributes of an object (from design perspective) and they are kept private to implement encapsulation. These variables can only be accessed using the public member functions.

Let us put above concepts to set and get the value of different class members in a class −

Constructors and Destructors

A class constructor is a special member Sub of a class that is executed whenever we create new objects of that class. A constructor has the name New and it does not have any return type.

Following program explains the concept of constructor −

A default constructor does not have any parameter, but if you need, a constructor can have parameters. Such constructors are called parameterized constructors . This technique helps you to assign initial value to an object at the time of its creation as shown in the following example −

A destructor is a special member Sub of a class that is executed whenever an object of its class goes out of scope.

A destructor has the name Finalize and it can neither return a value nor can it take any parameters. Destructor can be very useful for releasing resources before coming out of the program like closing files, releasing memories, etc.

Destructors cannot be inherited or overloaded.

Following example explains the concept of destructor −

Shared Members of a VB.Net Class

We can define class members as static using the Shared keyword. When we declare a member of a class as Shared, it means no matter how many objects of the class are created, there is only one copy of the member.

The keyword Shared implies that only one instance of the member exists for a class. Shared variables are used for defining constants because their values can be retrieved by invoking the class without creating an instance of it.

Shared variables can be initialized outside the member function or class definition. You can also initialize Shared variables inside the class definition.

You can also declare a member function as Shared. Such functions can access only Shared variables. The Shared functions exist even before the object is created.

The following example demonstrates the use of shared members −

Inheritance

One of the most important concepts in object-oriented programming is that of inheritance. Inheritance allows us to define a class in terms of another class which makes it easier to create and maintain an application. This also provides an opportunity to reuse the code functionality and fast implementation time.

When creating a class, instead of writing completely new data members and member functions, the programmer can designate that the new class should inherit the members of an existing class. This existing class is called the base class, and the new class is referred to as the derived class.

Base & Derived Classes

A class can be derived from more than one class or interface, which means that it can inherit data and functions from multiple base classes or interfaces.

The syntax used in VB.Net for creating derived classes is as follows −

Consider a base class Shape and its derived class Rectangle −

Base Class Initialization

The derived class inherits the base class member variables and member methods. Therefore, the super class object should be created before the subclass is created. The super class or the base class is implicitly known as MyBase in VB.Net

The following program demonstrates this −

VB.Net supports multiple inheritance.

An exception is a problem that arises during the execution of a program. An exception is a response to an exceptional circumstance that arises while a program is running, such as an attempt to divide by zero.

Exceptions provide a way to transfer control from one part of a program to another. VB.Net exception handling is built upon four keywords - Try , Catch , Finally and Throw .

Try − A Try block identifies a block of code for which particular exceptions will be activated. It's followed by one or more Catch blocks.

Catch − A program catches an exception with an exception handler at the place in a program where you want to handle the problem. The Catch keyword indicates the catching of an exception.

Finally − The Finally block is used to execute a given set of statements, whether an exception is thrown or not thrown. For example, if you open a file, it must be closed whether an exception is raised or not.

Throw − A program throws an exception when a problem shows up. This is done using a Throw keyword.

Assuming a block will raise an exception, a method catches an exception using a combination of the Try and Catch keywords. A Try/Catch block is placed around the code that might generate an exception. Code within a Try/Catch block is referred to as protected code, and the syntax for using Try/Catch looks like the following −

You can list down multiple catch statements to catch different type of exceptions in case your try block raises more than one exception in different situations.

Exception Classes in .Net Framework

In the .Net Framework, exceptions are represented by classes. The exception classes in .Net Framework are mainly directly or indirectly derived from the System.Exception class. Some of the exception classes derived from the System.Exception class are the System.ApplicationException and System.SystemException classes.

The System.ApplicationException class supports exceptions generated by application programs. So the exceptions defined by the programmers should derive from this class.

The System.SystemException class is the base class for all predefined system exception.

The following table provides some of the predefined exception classes derived from the Sytem.SystemException class −

Handling Exceptions

VB.Net provides a structured solution to the exception handling problems in the form of try and catch blocks. Using these blocks the core program statements are separated from the error-handling statements.

These error handling blocks are implemented using the Try , Catch and Finally keywords. Following is an example of throwing an exception when dividing by zero condition occurs −

Creating User-Defined Exceptions

You can also define your own exception. User-defined exception classes are derived from the ApplicationException class. The following example demonstrates this −

Throwing Objects

You can throw an object if it is either directly or indirectly derived from the System.Exception class.

You can use a throw statement in the catch block to throw the present object as −

A file is a collection of data stored in a disk with a specific name and a directory path. When a file is opened for reading or writing, it becomes a stream .

The stream is basically the sequence of bytes passing through the communication path. There are two main streams: the input stream and the output stream . The input stream is used for reading data from file (read operation) and the output stream is used for writing into the file (write operation).

VB.Net I/O Classes

The System.IO namespace has various classes that are used for performing various operations with files, like creating and deleting files, reading from or writing to a file, closing a file, etc.

The following table shows some commonly used non-abstract classes in the System.IO namespace −

The FileStream Class

The FileStream class in the System.IO namespace helps in reading from, writing to and closing files. This class derives from the abstract class Stream.

You need to create a FileStream object to create a new file or open an existing file. The syntax for creating a FileStream object is as follows −

For example, for creating a FileStream object F for reading a file named sample.txt −

The following program demonstrates use of the FileStream class −

Advanced File Operations in VB.Net

The preceding example provides simple file operations in VB.Net. However, to utilize the immense powers of System.IO classes, you need to know the commonly used properties and methods of these classes.

We will discuss these classes and the operations they perform in the following sections. Please click the links provided to get to the individual sections −

An object is a type of user interface element you create on a Visual Basic form by using a toolbox control. In fact, in Visual Basic, the form itself is an object. Every Visual Basic control consists of three important elements −

Properties which describe the object,

Methods cause an object to do something and

Events are what happens when an object does something.

Control Properties

All the Visual Basic Objects can be moved, resized or customized by setting their properties. A property is a value or characteristic held by a Visual Basic object, such as Caption or Fore Color.

Properties can be set at design time by using the Properties window or at run time by using statements in the program code.

Object is the name of the object you're customizing.

Property is the characteristic you want to change.

Value is the new property setting.

You can set any of the form properties using Properties Window. Most of the properties can be set or read during application execution. You can refer to Microsoft documentation for a complete list of properties associated with different controls and restrictions applied to them.

Control Methods

A method is a procedure created as a member of a class and they cause an object to do something. Methods are used to access or manipulate the characteristics of an object or a variable. There are mainly two categories of methods you will use in your classes −

If you are using a control such as one of those provided by the Toolbox, you can call any of its public methods. The requirements of such a method depend on the class being used.

If none of the existing methods can perform your desired task, you can add a method to a class.

For example, the MessageBox control has a method named Show, which is called in the code snippet below −

Control Events

An event is a signal that informs an application that something important has occurred. For example, when a user clicks a control on a form, the form can raise a Click event and call a procedure that handles the event. There are various types of events associated with a Form like click, double click, close, load, resize, etc.

Following is the default structure of a form Load event handler subroutine. You can see this code by double clicking the code which will give you a complete list of the all events associated with Form control −

Here, Handles MyBase.Load indicates that Form1_Load() subroutine handles Load event. Similar way, you can check stub code for click, double click. If you want to initialize some variables like properties, etc., then you will keep such code inside Form1_Load() subroutine. Here, important point to note is the name of the event handler, which is by default Form1_Load, but you can change this name based on your naming convention you use in your application programming.

Basic Controls

VB.Net provides a huge variety of controls that help you to create rich user interface. Functionalities of all these controls are defined in the respective control classes. The control classes are defined in the System.Windows.Forms namespace.

The following table lists some of the commonly used controls −

There are many built-in dialog boxes to be used in Windows forms for various tasks like opening and saving files, printing a page, providing choices for colors, fonts, page setup, etc., to the user of an application. These built-in dialog boxes reduce the developer's time and workload.

All of these dialog box control classes inherit from the CommonDialog class and override the RunDialog() function of the base class to create the specific dialog box.

The RunDialog() function is automatically invoked when a user of a dialog box calls its ShowDialog() function.

The ShowDialog method is used to display all the dialog box controls at run-time. It returns a value of the type of DialogResult enumeration. The values of DialogResult enumeration are −

Abort − returns DialogResult.Abort value, when user clicks an Abort button.

Cancel − returns DialogResult.Cancel, when user clicks a Cancel button.

Ignore − returns DialogResult.Ignore, when user clicks an Ignore button.

No − returns DialogResult.No, when user clicks a No button.

None − returns nothing and the dialog box continues running.

OK − returns DialogResult.OK, when user clicks an OK button

Retry − returns DialogResult.Retry , when user clicks an Retry button

Yes − returns DialogResult.Yes, when user clicks an Yes button

The following diagram shows the common dialog class inheritance −

All these above-mentioned classes have corresponding controls that could be added from the Toolbox during design time. You can include relevant functionality of these classes to your application, either by instantiating the class programmatically or by using relevant controls.

When you double click any of the dialog controls in the toolbox or drag the control onto the form, it appears in the Component tray at the bottom of the Windows Forms Designer, they do not directly show up on the form.

The following table lists the commonly used dialog box controls. Click the following links to check their detail −

VB.Net - Advanced Form

In this chapter, let us study the following concepts −

Adding menus and sub menus in an application

Adding the cut, copy and paste functionalities in a form

Anchoring and docking controls in a form

Modal forms

Adding Menus and Sub Menus in an Application

Traditionally, the Menu , MainMenu , ContextMenu , and MenuItem classes were used for adding menus, sub-menus and context menus in a Windows application.

Now, the MenuStrip , the ToolStripMenuItem , ToolStripDropDown and ToolStripDropDownMenu controls replace and add functionality to the Menu-related controls of previous versions. However, the old control classes are retained for both backward compatibility and future use.

Let us create a typical windows main menu bar and sub menus using the old version controls first since these controls are still much used in old applications.

Following is an example, which shows how we create a menu bar with menu items: File, Edit, View and Project. The File menu has the sub menus New, Open and Save.

Let's double click on the Form and put the following code in the opened window.

When the above code is executed and run using Start button available at the Microsoft Visual Studio tool bar, it will show the following window −

Windows Forms contain a rich set of classes for creating your own custom menus with modern appearance, look and feel. The MenuStrip , ToolStripMenuItem , ContextMenuStrip controls are used to create menu bars and context menus efficiently.

Click the following links to check their details −

Adding the Cut, Copy and Paste Functionalities in a Form

The methods exposed by the ClipBoard class are used for adding the cut, copy and paste functionalities in an application. The ClipBoard class provides methods to place data on and retrieve data from the system Clipboard.

It has the following commonly used methods −

Following is an example, which shows how we cut, copy and paste data using methods of the Clipboard class. Take the following steps −

Add a rich text box control and three button controls on the form.

Change the text property of the buttons to Cut, Copy and Paste, respectively.

Double click on the buttons to add the following code in the code editor −

Enter some text and check how the buttons work.

Anchoring and Docking Controls in a Form

Anchoring allows you to set an anchor position for a control to the edges of its container control, for example, the form. The Anchor property of the Control class allows you to set values of this property. The Anchor property gets or sets the edges of the container to which a control is bound and determines how a control is resized with its parent.

When you anchor a control to a form, the control maintains its distance from the edges of the form and its anchored position, when the form is resized.

You can set the Anchor property values of a control from the Properties window −

For example, let us add a Button control on a form and set its anchor property to Bottom, Right. Run this form to see the original position of the Button control with respect to the form.

Now, when you stretch the form, the distance between the Button and the bottom right corner of the form remains same.

Docking of a control means docking it to one of the edges of its container. In docking, the control fills certain area of the container completely.

The Dock property of the Control class does this. The Dock property gets or sets which control borders are docked to its parent control and determines how a control is resized with its parent.

You can set the Dock property values of a control from the Properties window −

For example, let us add a Button control on a form and set its Dock property to Bottom. Run this form to see the original position of the Button control with respect to the form.

Now, when you stretch the form, the Button resizes itself with the form.

Modal Forms

Modal Forms are those forms that need to be closed or hidden before you can continue working with the rest of the application. All dialog boxes are modal forms. A MessageBox is also a modal form.

You can call a modal form by two ways −

Calling the ShowDialog method

Calling the Show method

Let us take up an example in which we will create a modal form, a dialog box. Take the following steps −

Add a form, Form1 to your application, and add two labels and a button control to Form1

Change the text properties of the first label and the button to 'Welcome to Tutorials Point' and 'Enter your Name', respectively. Keep the text properties of the second label as blank.

Add a new Windows Form, Form2, and add two buttons, one label, and a text box to Form2.

Change the text properties of the buttons to OK and Cancel, respectively. Change the text properties of the label to 'Enter your name:'.

Set the FormBorderStyle property of Form2 to FixedDialog , for giving it a dialog box border.

Set the ControlBox property of Form2 to False.

Set the ShowInTaskbar property of Form2 to False.

Set the DialogResult property of the OK button to OK and the Cancel button to Cancel.

Add the following code snippets in the Form2_Load method of Form2 −

Add the following code snippets in the Button1_Click method of Form1 −

Clicking on the 'Enter your Name' button displays the second form −

Clicking on the OK button takes the control and information back from the modal form to the previous form −

Events are basically a user action like key press, clicks, mouse movements, etc., or some occurrence like system generated notifications. Applications need to respond to events when they occur.

Clicking on a button, or entering some text in a text box, or clicking on a menu item, all are examples of events. An event is an action that calls a function or may cause another event. Event handlers are functions that tell how to respond to an event.

VB.Net is an event-driven language. There are mainly two types of events −

Mouse events

Keyboard events

Handling Mouse Events

Mouse events occur with mouse movements in forms and controls. Following are the various mouse events related with a Control class −

MouseDown − it occurs when a mouse button is pressed

MouseEnter − it occurs when the mouse pointer enters the control

MouseHover − it occurs when the mouse pointer hovers over the control

MouseLeave − it occurs when the mouse pointer leaves the control

MouseMove − it occurs when the mouse pointer moves over the control

MouseUp − it occurs when the mouse pointer is over the control and the mouse button is released

MouseWheel − it occurs when the mouse wheel moves and the control has focus

The event handlers of the mouse events get an argument of type MouseEventArgs . The MouseEventArgs object is used for handling mouse events. It has the following properties −

Buttons − indicates the mouse button pressed

Clicks − indicates the number of clicks

Delta − indicates the number of detents the mouse wheel rotated

X − indicates the x-coordinate of mouse click

Y − indicates the y-coordinate of mouse click

Following is an example, which shows how to handle mouse events. Take the following steps −

Add three labels, three text boxes and a button control in the form.

Change the text properties of the labels to - Customer ID, Name and Address, respectively.

Change the name properties of the text boxes to txtID, txtName and txtAddress, respectively.

Change the text property of the button to 'Submit'.

Add the following code in the code editor window −

Try to enter text in the text boxes and check the mouse events −

Handling Keyboard Events

Following are the various keyboard events related with a Control class −

KeyDown − occurs when a key is pressed down and the control has focus

KeyPress − occurs when a key is pressed and the control has focus

KeyUp − occurs when a key is released while the control has focus

The event handlers of the KeyDown and KeyUp events get an argument of type KeyEventArgs . This object has the following properties −

Alt − it indicates whether the ALT key is pressed

Control − it indicates whether the CTRL key is pressed

Handled − it indicates whether the event is handled

KeyCode − stores the keyboard code for the event

KeyData − stores the keyboard data for the event

KeyValue − stores the keyboard value for the event

Modifiers − it indicates which modifier keys (Ctrl, Shift, and/or Alt) are pressed

Shift − it indicates if the Shift key is pressed

Handled − indicates if the KeyPress event is handled

KeyChar − stores the character corresponding to the key pressed

Let us continue with the previous example to show how to handle keyboard events. The code will verify that the user enters some numbers for his customer ID and age.

Add a label with text Property as 'Age' and add a corresponding text box named txtAge.

Add the following codes for handling the KeyUP events of the text box txtID.

If you leave the text for age or ID as blank or enter some non-numeric data, it gives a warning message box and clears the respective text −

A regular expression is a pattern that could be matched against an input text. The .Net framework provides a regular expression engine that allows such matching. A pattern consists of one or more character literals, operators, or constructs.

Constructs for Defining Regular Expressions

There are various categories of characters, operators, and constructs that lets you to define regular expressions. Click the following links to find these constructs.

Character escapes

Character classes

Grouping constructs

Quantifiers

Backreference constructs

Alternation constructs

Substitutions

Miscellaneous constructs

The Regex Class

The Regex class is used for representing a regular expression.

The Regex class has the following commonly used methods −

For the complete list of methods and properties, please consult Microsoft documentation.

The following example matches words that start with 'S' −

The following example matches words that start with 'm' and ends with 'e' −

This example replaces extra white space −

Applications communicate with a database, firstly, to retrieve the data stored there and present it in a user-friendly way, and secondly, to update the database by inserting, modifying and deleting data.

Microsoft ActiveX Data Objects.Net (ADO.Net) is a model, a part of the .Net framework that is used by the .Net applications for retrieving, accessing and updating data.

ADO.Net Object Model

ADO.Net object model is nothing but the structured process flow through various components. The object model can be pictorially described as −

The data residing in a data store or database is retrieved through the data provider . Various components of the data provider retrieve data for the application and update data.

An application accesses data either through a dataset or a data reader.

Datasets store data in a disconnected cache and the application retrieves data from it.

Data readers provide data to the application in a read-only and forward-only mode.

Data Provider

A data provider is used for connecting to a database, executing commands and retrieving data, storing it in a dataset, reading the retrieved data and updating the database.

The data provider in ADO.Net consists of the following four objects −

There are following different types of data providers included in ADO.Net

The .Net Framework data provider for SQL Server - provides access to Microsoft SQL Server.

The .Net Framework data provider for OLE DB - provides access to data sources exposed by using OLE DB.

The .Net Framework data provider for ODBC - provides access to data sources exposed by ODBC.

The .Net Framework data provider for Oracle - provides access to Oracle data source.

The EntityClient provider - enables accessing data through Entity Data Model (EDM) applications.

DataSet is an in-memory representation of data. It is a disconnected, cached set of records that are retrieved from a database. When a connection is established with the database, the data adapter creates a dataset and stores data in it. After the data is retrieved and stored in a dataset, the connection with the database is closed. This is called the 'disconnected architecture'. The dataset works as a virtual database containing tables, rows, and columns.

The following diagram shows the dataset object model −

The DataSet class is present in the System.Data namespace. The following table describes all the components of DataSet −

Connecting to a Database

The .Net Framework provides two types of Connection classes −

SqlConnection − designed for connecting to Microsoft SQL Server.

OleDbConnection − designed for connecting to a wide range of databases, like Microsoft Access and Oracle.

We have a table stored in Microsoft SQL Server, named Customers, in a database named testDB. Please consult 'SQL Server' tutorial for creating databases and database tables in SQL Server.

Let us connect to this database. Take the following steps −

Select TOOLS → Connect to Database

Select a server name and the database name in the Add Connection dialog box.

Click on the Test Connection button to check if the connection succeeded.

Add a DataGridView on the form.

Click on the Choose Data Source combo box.

Click on the Add Project Data Source link.

This opens the Data Source Configuration Wizard.

Select Database as the data source type

Choose DataSet as the database model.

Choose the connection already set up.

Save the connection string.

Choose the database object, Customers table in our example, and click the Finish button.

Select the Preview Data link to see the data in the Results grid −

When the application is run using Start button available at the Microsoft Visual Studio tool bar, it will show the following window −

In this example, let us access data in a DataGridView control using code. Take the following steps −

Add a DataGridView control and a button in the form.

Change the text of the button control to 'Fill'.

Double click the button control to add the required code for the Click event of the button, as shown below −

Clicking the Fill button displays the table on the data grid view control −

Creating Table, Columns and Rows

We have discussed that the DataSet components like DataTable, DataColumn and DataRow allow us to create tables, columns and rows, respectively.

The following example demonstrates the concept −

So far, we have used tables and databases already existing in our computer. In this example, we will create a table, add columns, rows and data into it and display the table using a DataGridView object.

Take the following steps −

Add the following code in the code editor.

VB.Net provides support for interoperability between the COM object model of Microsoft Excel 2010 and your application.

To avail this interoperability in your application, you need to import the namespace Microsoft.Office.Interop.Excel in your Windows Form Application.

Creating an Excel Application from VB.Net

Let's start with creating a Window Forms Application by following the following steps in Microsoft Visual Studio: File → New Project → Windows Forms Applications

Finally, select OK, Microsoft Visual Studio creates your project and displays following Form1 .

Insert a Button control Button1 in the form.

Add a reference to Microsoft Excel Object Library to your project. To do this −

Select Add Reference from the Project Menu.

On the COM tab, locate Microsoft Excel Object Library and then click Select.

Double click the code window and populate the Click event of Button1, as shown below.

Clicking on the Button would display the following excel sheet. You will be asked to save the workbook.

VB.Net allows sending e-mails from your application. The System.Net.Mail namespace contains classes used for sending e-mails to a Simple Mail Transfer Protocol (SMTP) server for delivery.

The following table lists some of these commonly used classes −

The SmtpClient Class

The SmtpClient class allows applications to send e-mail by using the Simple Mail Transfer Protocol (SMTP).

Following are some commonly used properties of the SmtpClient class −

Following are some commonly used methods of the SmtpClient class −

The following example demonstrates how to send mail using the SmtpClient class. Following points are to be noted in this respect −

You must specify the SMTP host server that you use to send e-mail. The Host and Port properties will be different for different host server. We will be using gmail server.

You need to give the Credentials for authentication, if required by the SMTP server.

You should also provide the email address of the sender and the e-mail address or addresses of the recipients using the MailMessage.From and MailMessage.To properties, respectively.

You should also specify the message content using the MailMessage.Body property.

In this example, let us create a simple application that would send an e-mail. Take the following steps −

Change the text properties of the labels to - 'From', 'To:' and 'Message:' respectively.

Change the name properties of the texts to txtFrom, txtTo and txtMessage respectively.

Change the text property of the button control to 'Send'

You must provide your gmail address and real password for credentials.

When the above code is executed and run using Start button available at the Microsoft Visual Studio tool bar, it will show the following window, which you will use to send your e-mails, try it yourself.

The Extensible Markup Language (XML) is a markup language much like HTML or SGML. This is recommended by the World Wide Web Consortium and available as an open standard.

The System.Xml namespace in the .Net Framework contains classes for processing XML documents. Following are some of the commonly used classes in the System.Xml namespace.

XML Parser APIs

The two most basic and broadly used APIs to XML data are the SAX and DOM interfaces.

Simple API for XML (SAX) − Here, you register callbacks for events of interest and then let the parser proceed through the document. This is useful when your documents are large or you have memory limitations, it parses the file as it reads it from disk, and the entire file is never stored in memory.

Document Object Model (DOM) API − This is World Wide Web Consortium recommendation wherein the entire file is read into memory and stored in a hierarchical (tree-based) form to represent all the features of an XML document.

SAX obviously can't process information as fast as DOM can when working with large files. On the other hand, using DOM exclusively can really kill your resources, especially if used on a lot of small files.

SAX is read-only, while DOM allows changes to the XML file. Since these two different APIs literally complement each other there is no reason why you can't use them both for large projects.

For all our XML code examples, let's use a simple XML file movies.xml as an input −

Parsing XML with SAX API

In SAX model, you use the XmlReader and XmlWriter classes to work with the XML data.

The XmlReader class is used to read XML data in a fast, forward-only and non-cached manner. It reads an XML document or a stream.

This example demonstrates reading XML data from the file movies.xml.

Add the movies.xml file in the bin\Debug folder of your application.

Import the System.Xml namespace in Form1.vb file.

Add a label in the form and change its text to 'Movies Galore'.

Add three list boxes and three buttons to show the title, type and description of a movie from the xml file.

Add the following code using the code editor window.

Execute and run the above code using Start button available at the Microsoft Visual Studio tool bar. Clicking on the buttons would display, title, type and description of the movies from the file.

The XmlWriter class is used to write XML data into a stream, a file or a TextWriter object. It also works in a forward-only, non-cached manner.

Let us create an XML file by adding some data at runtime. Take the following steps −

Add a WebBrowser control and a button control in the form.

Change the Text property of the button to Show Authors File.

Execute and run the above code using Start button available at the Microsoft Visual Studio tool bar. Clicking on the Show Author File would display the newly created authors.xml file on the web browser.

Parsing XML with DOM API

According to the Document Object Model (DOM), an XML document consists of nodes and attributes of the nodes. The XmlDocument class is used to implement the XML DOM parser of the .Net Framework. It also allows you to modify an existing XML document by inserting, deleting or updating data in the document.

Following are some of the commonly used methods of the XmlDocument class −

In this example, let us insert some new nodes in the xml document authors.xml and then show all the authors' first names in a list box.

Add the authors.xml file in the bin/Debug folder of your application( it should be there if you have tried the last example)

Import the System.Xml namespace

Add a list box and a button control in the form and set the text property of the button control to Show Authors.

Add the following code using the code editor.

Execute and run the above code using Start button available at the Microsoft Visual Studio tool bar. Clicking on the Show Author button would display the first names of all the authors including the one we have added at runtime.

A dynamic web application consists of either or both of the following two types of programs −

Server-side scripting − these are programs executed on a web server, written using server-side scripting languages like ASP (Active Server Pages) or JSP (Java Server Pages).

Client-side scripting − these are programs executed on the browser, written using scripting languages like JavaScript, VBScript, etc.

ASP.Net is the .Net version of ASP, introduced by Microsoft, for creating dynamic web pages by using server-side scripts. ASP.Net applications are compiled codes written using the extensible and reusable components or objects present in .Net framework. These codes can use the entire hierarchy of classes in .Net framework.

The ASP.Net application codes could be written in either of the following languages −

Visual Basic .Net

In this chapter, we will give a very brief introduction to writing ASP.Net applications using VB.Net. For detailed discussion, please consult the ASP.Net Tutorial.

ASP.Net Built-in Objects

ASP.Net has some built-in objects that run on a web server. These objects have methods, properties and collections that are used in application development.

The following table lists the ASP.Net built-in objects with a brief description −

ASP.Net Programming Model

ASP.Net provides two types of programming models −

Web Forms − this enables you to create the user interface and the application logic that would be applied to various components of the user interface.

WCF Services − this enables you to remote access some server-side functionalities.

For this chapter, you need to use Visual Studio Web Developer, which is free. The IDE is almost same as you have already used for creating the Windows Applications.

Web forms consists of −

User interface

Application logic

User interface consists of static HTML or XML elements and ASP.Net server controls. When you create a web application, HTML or XML elements and server controls are stored in a file with .aspx extension. This file is also called the page file.

The application logic consists of code applied to the user interface elements in the page. You write this code in any of .Net language like, VB.Net, or C#. The following figure shows a Web Form in Design view −

Let us create a new web site with a web form, which will show the current date and time, when a user clicks a button. Take the following steps −

Select File → New → Web Site. The New Web Site Dialog Box appears.

Select the ASP.Net Empty Web Site templates. Type a name for the web site and select a location for saving the files.

You need to add a Default page to the site. Right click the web site name in the Solution Explorer and select Add New Item option from the context menu. The Add New Item dialog box is displayed −

Select Web Form option and provide a name for the default page. We have kept it as Default.aspx. Click the Add button.

The Default page is shown in Source view

Set the title for the Default web page by adding a value to the <Title> tag of the page, in the Source view −

To add controls on the web page, go to the design view. Add three labels, a text box and a button on the form.

Double-click the button and add the following code to the Click event of the button −

When the above code is executed and run using Start button available at the Microsoft Visual Studio tool bar, the following page opens in the browser −

Enter your name and click on the Submit button −

Web Services

A web service is a web application, which is basically a class consisting of methods that could be used by other applications. It also follows a code-behind architecture like the ASP.Net web pages, although it does not have an user interface.

The previous versions of .Net Framework used this concept of ASP.Net Web Service, which had .asmx file extension. However, from .Net Framework 4.0 onwards, the Windows Communication Foundation (WCF) technology has evolved as the new successor of Web Services, .Net Remoting and some other related technologies. It has rather clubbed all these technologies together. In the next section, we will provide a brief introduction to Windows Communication Foundation(WCF).

If you are using previous versions of .Net Framework, you can still create traditional web services. Please consult ASP.Net - Web Services tutorial for detailed description.

Windows Communication Foundation

Windows Communication Foundation or WCF provides an API for creating distributed service-oriented applications, known as WCF Services.

Like Web services, WCF services also enable communication between applications. However, unlike web services, the communication here is not limited to HTTP only. WCF can be configured to be used over HTTP, TCP, IPC, and Message Queues. Another strong point in favour of WCF is, it provides support for duplex communication, whereas with web services we could achieve simplex communication only.

From beginners' point of view, writing a WCF service is not altogether so different from writing a Web Service. To keep the things simple, we will see how to −

Create a WCF Service

Create a Service Contract and define the operations

Implement the contract

Test the Service

Utilize the Service

To understand the concept let us create a simplistic service that will provide stock price information. The clients can query about the name and price of a stock based on the stock symbol. To keep this example simple, the values are hardcoded in a two-dimensional array. This service will have two methods −

GetPrice Method − it will return the price of a stock, based on the symbol provided.

GetName Method − it will return the name of the stock, based on the symbol provided.

Creating a WCF Service

Open VS Express for Web 2012

Select New Web Site to open the New Web Site dialog box.

Select WCF Service template from list of templates −

Select File System from the Web location drop-down list.

Provide a name and location for the WCF Service and click OK.

A new WCF Service is created.

Creating a Service Contract and Defining the Operations

A service contract defines the operation that a service performs. In the WCF Service application, you will find two files automatically created in the App_Code folder in the Solution Explorer

IService.vb − this will have the service contract; in simpler words, it will have the interface for the service, with the definitions of methods the service will provide, which you will implement in your service.

Service.vb − this will implement the service contract.

Replace the code of the IService.vb file with the given code −

Implementing the Contract

In the Service.vb file, you will find a class named Service which will implement the Service Contract defined in the IService interface.

Replace the code of IService.vb with the following code −

Testing the Service

To run the WCF Service, so created, select the Debug → Start Debugging option from the menu bar. The output would be −

For testing the service operations, double click the name of the operation from the tree on the left pane. A new tab will appear on the right pane.

Enter the value of parameters in the Request area of the right pane and click the 'Invoke' button.

The following diagram displays the result of testing the GetPrice operation −

The following diagram displays the result of testing the GetName operation −

Utilizing the Service

Let us add a default page, a ASP.NET web form in the same solution from which we will be using the WCF Service we have just created.

Right click on the solution name in the Solution Explorer and add a new web form to the solution. It will be named Default.aspx.

Add two labels, a text box and a button on the form.

We need to add a service reference to the WCF service we just created. Right click the website in the Solution Explorer and select Add Service Reference option. This opens the Add Service Reference Dialog box.

Enter the URL(location) of the Service in the Address text box and click the Go button. It creates a service reference with the default name ServiceReference1 . Click the OK button.

Adding the reference does two jobs for your project −

Creates the Address and Binding for the service in the web.config file.

Creates a proxy class to access the service.

Double click the Get Price button in the form, to enter the following code snippet on its Click event −

Enter a symbol and click the Get Price button to get the hard-coded price −