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 −

Ø  Namespace declaration

Ø  A class or module

Ø  One or more procedures

Ø  Variables

Ø  The Main procedure

Ø  Statements & Expressions

Ø  Comments

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 −

Hello, World!

Let us look various parts of the above program −

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

Ø  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.

Ø  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 −

Ø  Function

Ø  Sub

Ø  Operator

Ø  Get

Ø  Set

Ø  AddHandler

Ø  RemoveHandler

Ø  RaiseEvent

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

Ø  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.

Ø  The Main procedure specifies its behavior with the statement

Ø  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.

Ø  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 −

Ø  Start Visual Studio.

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

Ø  Choose Visual Basic from templates

Ø  Choose Console Application.

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

Ø  The new project appears in Solution Explorer.

Ø  Write code in the Code Editor.

Ø  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 –

Ø  Open a text editor and add the above mentioned code.

Ø  Save the file as helloworld.vb

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

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

Ø  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.

Ø  Next, type helloworld to execute your program.

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