A Beginner's Guide to Delegates

Module MulticastDelegates

    Public Delegate Sub GreetingDelegate(ByVal MsgString As String)

    Public Sub GoodMorning(ByVal YourName As String)
        Console.WriteLine("Good Morning " + YourName + " !")
    End Sub

    Public Sub GoodNight(ByVal YourName As String)
        Console.WriteLine("Good Night " + YourName + " !")
    End Sub

    Public Sub GoodEvening(ByVal YourName As String)
        Console.WriteLine("Good Evening " + YourName + " !")
    End Sub

    Sub Main()
        Dim MorningGreets As GreetingDelegate = AddressOf GoodMorning
        Dim EveningGreets As GreetingDelegate

        'MorningGreets()
        EveningGreets = New GreetingDelegate(AddressOf GoodEvening)

        Console.WriteLine()
        Console.WriteLine("Adding 'MoringGreets' And 'EveningGreets' References To A Delegate...")
        Dim AllGreets As GreetingDelegate = [Delegate].Combine(MorningGreets, EveningGreets)

        Console.WriteLine("Invoking Delegate...")
        AllGreets("Mallinath")

        Console.WriteLine()
        Console.WriteLine("Adding Another References To Existing Delegate...")
        AllGreets = [Delegate].Combine(AllGreets, New GreetingDelegate(AddressOf GoodNight))

        Console.WriteLine("Invoking Delegate...")
        AllGreets("Mallinath")

        Console.WriteLine()
        Console.WriteLine("Removing 'GoodEvening' Regerence...")
        Console.WriteLine("Invoking Delegate After Removing A 'GoodEvening'...")
        AllGreets = [Delegate].Remove(AllGreets, EveningGreets)
        AllGreets("Mallinath")

        Console.WriteLine()

    End Sub

End Module