' Visual Basic 2008 9.0 .NET Examples - Relaxed Delegates - New in Visual Basic 2008 - 9.0 : 
Option Strict Off
Class Counter
    Private m_Value As Short
    Public Sub New(ByVal value As Short)
        m_Value = value
    End Sub
    Public ReadOnly Property Value() As Short
        Get
            Value = m_Value
        End Get
    End Property
    Public Sub Raise()
        m_Value = System.Convert.ToInt16(m_Value + 1)
    End Sub
    Public Shared Widening Operator CType(ByVal counter As Counter) As Integer
        Return counter.Value
    End Operator
    Public Shared Narrowing Operator CType(ByVal value As Integer) As Counter
        Return New Counter(System.Convert.ToInt16(value))
    End Operator
End Class
Class Example1
    Public Delegate Function Delegate1(ByVal argument1 As Integer) As Integer
    Public Delegate Sub Delegate2(ByVal argument1 As Integer)
    Public Shared Sub Main()
        Dim delegate1a As Delegate1 = AddressOf Method1                    ' (1)
        Console.WriteLine(delegate1a.Invoke(1))
        '
        Dim delegate1b As Delegate1 = AddressOf Method2                    ' (2)
        Console.WriteLine(delegate1b.Invoke(1))
        '
        Dim delegate1c As Delegate1 = AddressOf Method3                    ' (3)
        Console.WriteLine(delegate1c.Invoke(1))
        '
        Dim delegate1d As Delegate1 = AddressOf Method4                    ' (4)
        Console.WriteLine(delegate1d.Invoke(1))
        '
        Dim delegate1e As Delegate1 = AddressOf Method5                    ' (5)
        Console.WriteLine(delegate1e.Invoke(1))
        '
        Dim delegate1f As Delegate1 = AddressOf Method6                    ' (6)
        Console.WriteLine(delegate1f.Invoke(1))
        '
        Dim delegate1g As Delegate1 = AddressOf Method7                    ' (7)
        Console.WriteLine(delegate1g.Invoke(1))
        '
        Dim delegate2a As Delegate2 = AddressOf Method1                    ' (8)
        delegate2a.Invoke(1)
        '
        Console.ReadLine()
    End Sub
    Public Shared Function Method1() As Integer
        Console.WriteLine("Method1")
        Method1 = 1
    End Function
    Public Shared Function Method2(ByVal argument1 As Long) As Integer
        Method2 = 2
    End Function
    Public Shared Function Method3(ByVal argument1 As Short) As Integer
        Method3 = 3
    End Function
    Public Shared Function Method4(ByVal argument1 As Integer) As Short
        Method4 = 4
    End Function
    Public Shared Function Method5(ByVal argument1 As Integer) As Long
        Method5 = 5
    End Function
    Public Shared Function Method6(ByVal argument1 As Counter) As Integer
        Method6 = 6
    End Function
    Public Shared Function Method7(ByVal argument1 As Integer) As Counter
        Method7 = New Counter(7)
    End Function
End Class
Class Button
    'Public Delegate Sub ClickDelegate(ByVal sender As Object, _
    '                                  ByVal e As EventArgs)
    'Public Event Click As ClickDelegate
    ' or shorter :
    Public Event Click As EventHandler(Of EventArgs)
    Protected Sub OnClick()
        RaiseEvent Click(Me, EventArgs.Empty)
    End Sub
    Public Sub SimulateClick()
        OnClick()
    End Sub
End Class
Class Form
    Friend WithEvents Button1 As New Button
    Private Sub Button1_Click(ByVal sender As Object, _
                              ByVal e As EventArgs) Handles Button1.Click
        Console.WriteLine("Form.Button1_Click")
    End Sub
End Class
Class Example2
    Public Shared Sub Main()
        Dim form1 As New Form
        AddHandler form1.Button1.Click, AddressOf Button1_Click
        form1.Button1.SimulateClick()
        '
        Console.ReadLine()
    End Sub
    Private Shared Sub Button1_Click(ByVal sender As Object, _
                                     ByVal e As EventArgs)
        Console.WriteLine("Example2.Button1_Click")
    End Sub
End Class
Partial Class Form
    Friend WithEvents Button2 As New Button
    Private Sub Button2_Click() Handles Button2.Click                      ' (1)
        Console.WriteLine("Form.Button2_Click")
    End Sub
End Class
Class Example3
    Public Shared Sub Main()
        Dim form1 As New Form
        AddHandler form1.Button2.Click, AddressOf Button2_Click            ' (2)
        form1.Button2.SimulateClick()
        '
        Console.ReadLine()
    End Sub
    Private Shared Sub Button2_Click()
        Console.WriteLine("Example2.Button2_Click")
    End Sub
End Class

' Visit www.studyvb.com for more examples.  Copyright 2003-2008 De Wolf.