' Visual Basic 2008 9.0 .NET Examples - Extension Methods - New in Visual Basic 2008 - 9.0 : 
Public Class Counter
    Private m_Value As Integer
    Public ReadOnly Property Value() As Integer
        Get
            Value = m_Value
        End Get
    End Property
    Public Sub Raise()
        m_Value += 1
    End Sub
    Public Sub Lower()
        m_Value -= 1
    End Sub
    Public Overrides Function ToString() As String
        ToString = "Counter.Value : " & Value.ToString()
    End Function
End Class
Public Module CounterExtension
    <System.Runtime.CompilerServices.Extension()> _
    Public Function ToInt32(ByVal aCounter As Counter) As Integer
        ToInt32 = aCounter.Value
    End Function
    <System.Runtime.CompilerServices.Extension()> _
    Public Function ToString(ByVal aCounter As Counter) As String
        ToString = aCounter.Value.ToString()
    End Function
    <System.Runtime.CompilerServices.Extension()> _
    Public Function ToString(ByVal aCounter As Counter, _
                             ByVal paddingLength As Integer) As String     ' (1)
        ToString = aCounter.Value.ToString().PadLeft(paddingLength)
    End Function
End Module
Public Class Example2
    Public Shared Sub Main()
        Dim counter1 As New Counter
        counter1.Raise()
        counter1.Raise()
        '
        Dim integerValue1 As Integer = counter1.ToInt32()
        Console.WriteLine(integerValue1)
        '
        Dim stringValue1 As String = counter1.ToString()                   ' (2)
        Console.WriteLine(stringValue1)
        '
        Dim stringValue2 As String = counter1.ToString(3)                  ' (3)
        Console.WriteLine(stringValue2)
        '
        Console.ReadLine()
    End Sub
End Class
' Visit www.studyvb.com for more examples.  Copyright 2003-2008 De Wolf.