VB Language Fundamentals – Microsoft Docs

Overview

Visual Basic (VB) is a modern, object‑oriented programming language that makes it easy to write clear, concise, and maintainable code for .NET applications. This guide covers the core fundamentals you need to start building robust VB solutions.

Hello World

Every new language tutorial starts with a simple program that prints “Hello, World!” to the console.

Module HelloWorld
    Sub Main()
        Console.WriteLine("Hello, World!")
    End Sub
End Module

Compile and run with dotnet run inside a console project.

Variables & Data Types

VB provides strong typing with a range of built‑in types. Use Dim to declare a variable.

Dim name As String = "Alice"
Dim age As Integer = 30
Dim salary As Double = 5432.75
Dim isActive As Boolean = True

Optionally enable Option Strict On for compile‑time type checking.

Control Structures

VB supports the familiar If…Then…Else, Select Case, For, While, and Do…Loop constructs.

If age >= 18 Then
    Console.WriteLine("Adult")
Else
    Console.WriteLine("Minor")
End If

For i As Integer = 1 To 5
    Console.WriteLine(i)
Next

Select Case day
    Case "Saturday", "Sunday"
        Console.WriteLine("Weekend")
    Case Else
        Console.WriteLine("Weekday")
End Select

Functions & Subroutines

Encapsulate logic in Function (returns a value) or Sub (no return).

Function Add(a As Integer, b As Integer) As Integer
    Return a + b
End Function

Sub PrintGreeting(name As String)
    Console.WriteLine($"Hello, {name}!")
End Sub

' Usage
Dim sum = Add(3, 4)
PrintGreeting("Bob")

Error Handling

Use Try…Catch…Finally to handle runtime exceptions.

Try
    Dim result = 10 / Convert.ToInt32(userInput)
    Console.WriteLine($"Result: {result}")
Catch ex As DivideByZeroException
    Console.WriteLine("Cannot divide by zero.")
Catch ex As FormatException
    Console.WriteLine("Invalid number format.")
Finally
    Console.WriteLine("Operation completed.")
End Try

Classes & Objects

Define classes to model real‑world entities.

Public Class Person
    Public Property Name As String
    Public Property Age As Integer

    Public Sub New(name As String, age As Integer)
        Me.Name = name
        Me.Age = age
    End Sub

    Public Sub Greet()
        Console.WriteLine($"Hi, I'm {Name} and I'm {Age} years old.")
    End Sub
End Class

' Instantiate and use
Dim alice As New Person("Alice", 28)
alice.Greet()