Visual Basic

Overview

Definition and Purpose

Evolution and Family of Languages

History

Origins and Early Development (1980s–1990s)

Shift to .NET Framework (2000s)

Modern Updates and Support (2010s–Present)

Core Language Features

Syntax and Basic Constructs

Data Types and Variables

Control Structures and Error Handling

vb
' Example: Select Case for decision structure
Select Case dayOfWeek
    Case 1
        Console.WriteLine("Monday")
    Case 2, 3, 4, 5
        Console.WriteLine("Weekday")
    Case 6, 7
        Console.WriteLine("Weekend")
    Case Else
        Console.WriteLine("Invalid day")
End Select
' Example: Select Case for decision structure
Select Case dayOfWeek
    Case 1
        Console.WriteLine("Monday")
    Case 2, 3, 4, 5
        Console.WriteLine("Weekday")
    Case 6, 7
        Console.WriteLine("Weekend")
    Case Else
        Console.WriteLine("Invalid day")
End Select

vb
' Example: Do...Loop with condition
Dim counter As Integer = 0
Do While counter < 5
    counter += 1
    Console.WriteLine(counter)
Loop
' Example: Do...Loop with condition
Dim counter As Integer = 0
Do While counter < 5
    counter += 1
    Console.WriteLine(counter)
Loop

vb
' Example: With statement for object manipulation
Dim obj As New SomeObject()
With obj
    .Property1 = "Value1"
    .Property2 = "Value2"
    .MethodCall()
End With
' Example: With statement for object manipulation
Dim obj As New SomeObject()
With obj
    .Property1 = "Value1"
    .Property2 = "Value2"
    .MethodCall()
End With

vb
' Example: Sub procedure with parameters
Sub Greet(ByVal name As String, Optional ByRef greeting As String = "Hello")
    Console.WriteLine(greeting & ", " & name)
End Sub
' Example: Sub procedure with parameters
Sub Greet(ByVal name As String, Optional ByRef greeting As String = "Hello")
    Console.WriteLine(greeting & ", " & name)
End Sub

vb
' Example: Function with ParamArray
Function Sum(ParamArray numbers() As Integer) As Integer
    Dim total As Integer = 0
    For Each num In numbers
        total += num
    Next
    Return total
End Function
' Example: Function with ParamArray
Function Sum(ParamArray numbers() As Integer) As Integer
    Dim total As Integer = 0
    For Each num In numbers
        total += num
    Next
    Return total
End Function

vb
' Example: Exit For in loop
For i As Integer = 1 To 10
    If i > 5 Then Exit For
    Console.WriteLine(i)
Next
' Example: Exit For in loop
For i As Integer = 1 To 10
    If i > 5 Then Exit For
    Console.WriteLine(i)
Next

vb
' Example: On Error GoTo (classic VB)
On Error GoTo ErrorHandler
    ' Risky code
ErrorHandler:
    MsgBox(Err.Description)
    Resume Next
' Example: On Error GoTo (classic VB)
On Error GoTo ErrorHandler
    ' Risky code
ErrorHandler:
    MsgBox(Err.Description)
    Resume Next

vb
' Example: Try...Catch...Finally in VB.NET
Try
    ' Risky code, e.g., division by zero
    Dim result = 10 / 0
Catch ex As DivideByZeroException
    Console.WriteLine("Error: " & ex.Message)
Finally
    ' Cleanup
    Console.WriteLine("Execution completed")
End Try
' Example: Try...Catch...Finally in VB.NET
Try
    ' Risky code, e.g., division by zero
    Dim result = 10 / 0
Catch ex As DivideByZeroException
    Console.WriteLine("Error: " & ex.Message)
Finally
    ' Cleanup
    Console.WriteLine("Execution completed")
End Try

Object-Oriented Capabilities

Classes and Objects

vb
Public Class MyClass
    Public Sub New(ByVal initialValue As String)
        ' Initialization code here
    End Sub
End Class
Public Class MyClass
    Public Sub New(ByVal initialValue As String)
        ' Initialization code here
    End Sub
End Class

Inheritance and Polymorphism

vb
Class Circle
    Inherits Shape
    Overrides Function Area() As Double
        Return 3.14159 * Radius * Radius
    End Function
End Class
Class Circle
    Inherits Shape
    Overrides Function Area() As Double
        Return 3.14159 * Radius * Radius
    End Function
End Class

Events and Delegates

Variants and Implementations

Visual Basic for Applications (VBA)

VBScript and Other Scripting Variants

Visual Basic .NET (VB.NET)

vb
Dim contact As XElement = 
    <contact>
        <name><%= firstName %></name>
        <phone><%= phone %></phone>
    </contact>
Dim contact As XElement = 
    <contact>
        <name><%= firstName %></name>
        <phone><%= phone %></phone>
    </contact>

Development Tools and Environment

Integrated Development Environment (IDE)

Compilation and Runtime

Debugging and Deployment

Applications and Use Cases

Desktop and Windows Applications

Office Automation and Macros

Enterprise and Legacy Systems

Criticisms and Limitations

Performance and Modernity Issues

Comparison to Other Languages

Future Prospects and Migration Paths