「自定義事件」如何在VB.Net中工作？

Question

在C＃中，如果我想創建一個「自定義事件」你做這樣的事情：

private EventHandler _MyEvent; 
Public Event EventHandler MyEvent 
{ 
    add{ _MyEvent += value; } 
    remove{ _MyEvent -= Value; } 
} 
protected void RaiseMyEvent() 
{ 
    if(_MyEvent != nul) 
     _MyEvent(this, EventArgs.Empty); 
} 

在VB中，這不是那麼簡單也可以找到任何幫助，任何地方在網絡上。 這是行不通的：

private _MyEvent as EventHandler 
Public Custom Event MyEvent as EventHandler 
    AddHandler(ByVal value as EventHandler) 
     _MyEvent += value 'does not work 
     addhandler _MyEvent, value 'does not work 
     [Delegate].Combine(_MyEvent, value) '_MyEvent still nothing 
    End AddHandler 
    RemoveHandler(ByVal value as EventHandler) 
     'Same kind of stuff here 
    End RemoveHandler 
    RaiseEvent(sender as Object, e as EventArgs) 
     if(_MyEvent IsNot Nothing) Then '_MyEvent is always nothing 
     _MyEvent.Invoke(sender, e) 
     End If 
    End RaiseEvent 
End Event 

請幫忙。

Answer 1

委託是不可變的，所以方法「[委託] .Combine」返回新的委託，但不修改參數。所以你需要：

_MyEvent = [Delegate].Combine(_MyEvent, value) 

Answer 2

VB爲您混合了大量的工作。在代碼的任何地方

Public Event DidSomething(sender as object, e as EventArgs) 

然後，調用下跌引發事件

RaiseEvent DidSomething(me, EventArgs.Empty) 

Answer 3

...現在，如果你（或其他人的詢問）如何：

簡單地聲明事件創建方法處理該提出的事件，基於'DidSomething'的例子，你會這樣做如下：

Private Sub NowDoSomething(sender As Object, e As EventArgs) Handles Me.DidSomething 
    'Code for Event here 
End Sub