事件取消订阅 [英] Event unsubscribe

问题描述

我需要取消订阅我的活动中订阅的所有代表。但是我发现有两种方法可以实现。

I need to unsubscribe all delegates subscribed on my event. But I found two ways to do it..

class Cls
{
    delegate void doDel();
    static event doDel doE;

    void Uns
    {
    //first
    foreach (doDel item in doE.GetInvocationList())
    {
        doE -= item;
    }

    //second
       doE = null;
    }
}

之间有什么区别？什么方式是最好的，为什么？

What difference between? And what way is best and why?

推荐答案

第一种方法是非常正确的。如 MSDN 所述：

First approach is quite correct. As MSDN states:

• 使用减法赋值运算符（ - =）取消订阅事件：

• Use the subtraction assignment operator (-=) to unsubscribe from an event:

publisher.RaiseCustomEvent - = HandleCustomEvent;

publisher.RaiseCustomEvent -= HandleCustomEvent;

当所有订阅者已取消订阅事件中，发布商类中的事件
实例设置为null。

When all subscribers have unsubscribed from an event, the event instance in the publisher class is set to null.

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