事件处理程序和委托 [英] Event Handler and Delegate

问题描述

大家好，

我对事件处理程序有疑问，我在此事件处理程序/委托中确实很弱.
正常的事件处理程序，例如示例1，对我来说还是可以的，

示例1:

Hello all,

i have a question for the event handler, i''m really weak in this event handler/delegate.
normal event handler like example 1 still ok for me,

example 1 :

private abc as eventhandler
private sub MethodTest()
   addhandler me.abc, addressof Method1
End Sub

但是我看到一些代码像下面的示例2一样:

例子2:

but i see some code do like below example 2:

example 2 :

Private ZZZ As System.EventHandler = Nothing

private sub Method999()
   Me.ZZZ = New EventHandler(AddressOf Method1)
   <big>AddHandler me.AnotherEvent, me.ZZZ</big>
End Sub

private sub Method1(byval sender as object, byval e as eventArgs)
   'do something
End Sub

据我所知，示例1和示例2将执行相同的功能.
我不太了解如何使用代码.
希望有人为此提供帮助.

as what i know the example 1 and example 2 will perform the same function.
im not really understand how to use the code do like this.
hope somebody help me for this.

推荐答案

MSDN: EventHandler Delegate[^]

From reading the above article there is no technical difference between them except you are creating a eventhandler variable and assigning the addressof statement to that rather than the addhandler statement.

hope that makes sense

这是我过去所做的.希望对您有帮助.

一个单独的类，可以执行某些操作.

This is what I have done in the past. I hope this helps you.

A separate class that does something.

Public Class clsClassEvents
Event ReportFeedback(strMessage As String)

Public Sub DoSomething()
RaiseEvent ReportFeedback("I did something!")
End Sub
End Class

在我的主要形式中，我声明了我的课程，如下所示.

In my main form I declared my class as follows.

Private WithEvents myFeedback As New clsClassEvents()

Private Sub Form1_Load(sender As Object, e As System.EventArgs) Handles Me.Load
myFeedback.DoSomething()
End Sub

'Every time you call myFeedback.DoSomething() this Sub will be triggered.
Private Sub myFeedback_ReportFeedback(strMessage As String) Handles myFeedback.ReportFeedback
Me.Text = strMessage
End Sub

让我知道是否有帮助.

Let me know if this helps.

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