1:   AddHandler Button1.Click, New EventHandler(AddressOf Button1_Click) ' the same as line below

   2:   AddHandler Button1.Click, AddressOf Me.Button1_Click ' the same as line above

   3:   'EventHandler(AddressOf Button1_Click) - delegate

   1:   'Delegate Example 1

   2:   Dim inOrder As New InOrderClass

   3:   inOrder.Num1 = 5

   4:   inOrder.Num2 = 4

   5:   

   6:   'Use AddressOf to send a reference to the comparison function you want to use.

   7:   inOrder.ShowInOrder(AddressOf GreaterThan)

   8:   inOrder.ShowInOrder(AddressOf LessThan)

   9:   

  10:   'Use lambda expressions to do the same thing.

  11:   inOrder.ShowInOrder(Function(m, n) m > n)

  12:   inOrder.ShowInOrder(Function(m, n) m < n)

  13:   'Function(m, n) m < n  - Delegate

  14:   

  15:   

  16:    Function GreaterThan(ByVal num1 As Integer, ByVal num2 As Integer) As Boolean

  17:          Return num1 > num2

  18:    End Function

  19:   

  20:    Function LessThan(ByVal num1 As Integer, ByVal num2 As Integer) As Boolean

  21:          Return num1 < num2

  22:    End Function

  23:   

  24:    Class InOrderClass

  25:   

  26:          'Define the delegate function for the comparisons.

  27:          Delegate Function CompareNumbers(ByVal num1 As Integer, ByVal num2 As Integer) As Boolean

  28:   

  29:          'Display properties in ascending or descending order.

  30:          Sub ShowInOrder(ByVal compare As CompareNumbers)

  31:              If compare(_num1, _num2) Then

  32:                  Console.WriteLine(_num1 & "  " & _num2)

  33:              Else

  34:                  Console.WriteLine(_num2 & "  " & _num1)

  35:              End If

  36:          End Sub

  37:          Property Num1() As Integer

  38:          Property Num2() As Integer

  39:     End Class

   1:    'Delegate Example 2 - invoke delegate

   2:   

   3:    Delegate Function MathOperator(ByVal x As Double,  ByVal y As Double) As Double

   4:    Function AddNumbers(ByVal x As Double, ByVal y As Double) As Double

   5:      Return x + y

   6:    End Function

   7:    Function SubtractNumbers(ByVal x As Double, ByVal y As Double) As Double

   8:      Return x - y

   9:    End Function

  10:   

  11:    Sub DelegateCall(ByVal x As Double, ByVal op As MathOperator, ByVal y As Double)

  12:      Dim ret As Double

  13:      ret = op.Invoke(x, y) ' Call the method.

  14:      MsgBox(ret)

  15:    End Sub

  16:   

  17:    Protected Sub Test()

  18:      DelegateCall(5, AddressOf AddNumbers, 3)

  19:      DelegateCall(9, AddressOf SubtractNumbers, 3)

  20:    End Sub

   1:    Delegate Sub DelegateType()

   2:    Event AnEvent As DelegateType

   1:    'Event Example 1

   2:   

   3:    'Declare a WithEvents variable.

   4:    Dim WithEvents EClass As New EventClass

   5:   

   6:    'Declare an event handler that handles multiple events.

   7:    Sub EClass_EventHandler() Handles EClass.XEvent, EClass.YEvent

   8:       MsgBox("Received Event.")

   9:    End Sub

  10:   

  11:    Class EventClass

  12:        Public Event XEvent()

  13:        Public Event YEvent()

  14:        'RaiseEvents raises both events.

  15:        Sub FlashEvents()

  16:            RaiseEvent XEvent()

  17:            RaiseEvent YEvent()

  18:        End Sub

  19:    End Class

  20:   

  21:    EClass.FlashEvents()