Visual Basic .NET (VB.NET) Basics Cheat Sheet

1. Hello World (Basic Syntax)

Module Program
    Sub Main()
        Console.WriteLine("Hello, World!") ' Output text to console
        Console.ReadLine() ' Pause execution
    End Sub
End Module

• Module → Defines a module (container for procedures).
• Sub Main() → Entry point of the program.
• Console.WriteLine() → Outputs text.

2. Variables & Data Types

Dim age As Integer = 25       ' Integer
Dim price As Double = 9.99    ' Decimal number
Dim grade As Char = "A"c      ' Single character
Dim name As String = "John"   ' Text
Dim isActive As Boolean = True ' Boolean

• Dim → Declares a variable.
• Integer, Double, Char, String, Boolean → Common data types.

3. Constants

Const PI As Double = 3.14159 ' Cannot be changed

4. Operators

5. Conditionals

Dim num As Integer = 10

If num > 5 Then
    Console.WriteLine("Greater than 5")
ElseIf num = 5 Then
    Console.WriteLine("Equal to 5")
Else
    Console.WriteLine("Less than 5")
End If

6. Select Case (Switch)

Dim grade As Char = "A"c

Select Case grade
    Case "A"c
        Console.WriteLine("Excellent!")
    Case "B"c
        Console.WriteLine("Good!")
    Case Else
        Console.WriteLine("Invalid grade")
End Select

7. Loops

For Loop

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

While Loop

Dim count As Integer = 0
While count < 5
    Console.WriteLine(count)
    count += 1
End While

Do-While Loop

Dim num As Integer = 0
Do
    Console.WriteLine(num)
    num += 1
Loop While num < 5

8. Arrays

Dim numbers() As Integer = {1, 2, 3, 4, 5}
Console.WriteLine(numbers(0)) ' Outputs 1

9. Functions

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

Console.WriteLine(Add(3, 4)) ' Output: 7

10. Subroutines

Sub Greet(name As String)
    Console.WriteLine("Hello, " & name)
End Sub

Greet("Alice")

• Function → Returns a value.
• Sub → Does not return a value.

11. Classes & Objects

Class Car
    Public Brand As String

    Public Sub New(b As String)
        Brand = b
    End Sub
End Class

Dim myCar As New Car("Toyota")
Console.WriteLine(myCar.Brand)

• Class → Defines a blueprint.
• Object → Created using New.

12. Properties (Encapsulation)

Class Person
    Private _name As String

    Public Property Name() As String
        Get
            Return _name
        End Get
        Set(value As String)
            _name = value
        End Set
    End Property
End Class

Dim p As New Person()
p.Name = "Alice"
Console.WriteLine(p.Name) ' Output: Alice

13. Inheritance

Class Animal
    Public Sub MakeSound()
        Console.WriteLine("Some sound")
    End Sub
End Class

Class Dog
    Inherits Animal

    Public Sub Bark()
        Console.WriteLine("Woof!")
    End Sub
End Class

Dim myDog As New Dog()
myDog.MakeSound() ' Inherited method
myDog.Bark() ' Dog's own method

14. Polymorphism

Class Animal
    Overridable Sub Speak()
        Console.WriteLine("Animal sound")
    End Sub
End Class

Class Dog
    Inherits Animal

    Overrides Sub Speak()
        Console.WriteLine("Bark!")
    End Sub
End Class

Dim myAnimal As Animal = New Dog()
myAnimal.Speak() ' Output: Bark!

15. Interfaces

Interface IAnimal
    Sub MakeSound()
End Interface

Class Dog
    Implements IAnimal

    Public Sub MakeSound() Implements IAnimal.MakeSound
        Console.WriteLine("Bark!")
    End Sub
End Class

Dim myDog As New Dog()
myDog.MakeSound()

16. Exception Handling

Try
    Dim x As Integer = 10 / 0 ' Error
Catch ex As Exception
    Console.WriteLine("Error: " & ex.Message)
Finally
    Console.WriteLine("This runs no matter what.")
End Try

17. User Input

Console.Write("Enter your name: ")
Dim userName As String = Console.ReadLine()
Console.WriteLine("Hello, " & userName)

18. File Handling

Writing to a File

System.IO.File.WriteAllText("test.txt", "Hello World!")

Reading from a File

Dim content As String = System.IO.File.ReadAllText("test.txt")
Console.WriteLine(content)

19. Lists

Imports System.Collections.Generic

Dim names As New List(Of String) From {"Alice", "Bob"}
names.Add("Charlie")
Console.WriteLine(names(2)) ' Outputs Charlie

20. Dictionaries

Imports System.Collections.Generic

Dim ages As New Dictionary(Of String, Integer)
ages("Alice") = 25
ages("Bob") = 30

Console.WriteLine(ages("Alice")) ' 25

21. Asynchronous Programming

Imports System
Imports System.Threading.Tasks

Module Program
    Async Function DoWork() As Task
        Await Task.Delay(2000)
        Console.WriteLine("Work Done")
    End Function

    Async Sub Main()
        Await DoWork()
        Console.WriteLine("Main Finished")
    End Sub
End Module

Conclusion

This Visual Basic .NET Cheat Sheet covers:

• Basic Syntax
• Variables, Loops, Conditionals
• Object-Oriented Programming (Classes, Inheritance, Polymorphism)
• Exception Handling & File Handling
• Collections (Lists, Dictionaries)
• Asynchronous Programming

This serves as a quick reference guide to get started with VB.NET programming.