explizite hinzufügen/entfernen für Event in VB.net

Question

In C# können Sie explizit add/remove Code definieren, wenn ein event ist abonniert/abgemeldet.

Ist das in VB.net möglich?

Answer 1

Imports System.Runtime.CompilerServices 
... 
    Private propchanged As PropertyChangedEventHandler 

    Public Custom Event PropertyChanged As PropertyChangedEventHandler 

     <MethodImpl(MethodImplOptions.Synchronized)> _ 
     AddHandler(ByVal value As PropertyChangedEventHandler) 
      propchanged = DirectCast([Delegate].Combine(propchanged, value), PropertyChangedEventHandler) 
     End AddHandler 

     <MethodImpl(MethodImplOptions.Synchronized)> _ 
     RemoveHandler(ByVal value As PropertyChangedEventHandler) 
      propchanged = DirectCast([Delegate].Remove(propchanged, value), PropertyChangedEventHandler) 
     End RemoveHandler 

     RaiseEvent(ByVal sender As Object, ByVal e As System.ComponentModel.PropertyChangedEventArgs) 
      Dim handler = propchanged 
      If handler IsNot Nothing Then handler(sender, e) 
     End RaiseEvent 
    End Event 

Answer 2

Sieht aus wie es getan werden kann, benutzerdefinierte Ereignisse wie definiert here zu verwenden.

' Define the MouseDown event property. 
    Public Custom Event MouseDown As MouseEventHandler 
     ' Add the input delegate to the collection. 
     AddHandler(Value As MouseEventHandler) 
      listEventDelegates.AddHandler(mouseDownEventKey, Value) 
     End AddHandler 
     ' Remove the input delegate from the collection. 
     RemoveHandler(Value As MouseEventHandler) 
      listEventDelegates.RemoveHandler(mouseDownEventKey, Value) 
     End RemoveHandler 
     ' Raise the event with the delegate specified by mouseDownEventKey 
     RaiseEvent(sender As Object, e As MouseEventArgs) 
      Dim mouseEventDelegate As MouseEventHandler = _ 
       listEventDelegates(mouseDownEventKey) 
      mouseEventDelegate(sender, e) 
     End RaiseEvent 
    End Event