如何清除C＃中的事件订阅？ [英] How can I clear event subscriptions in C#?

问题描述

采取以下C＃类：

c1 {
 event EventHandler someEvent;
}

如果有很多订阅 c1 的 someEvent 事件，我想清除它们，什么是最好的方式来实现？ 还要考虑订阅此事件可能是/ lambdas /匿名代理。

If there are a lot of subscriptions to c1's someEvent event and I want to clear them all, what is the best way to achieve this? Also consider that subscriptions to this event could be/are lambdas/anonymous delegates.

目前我的解决方案是添加一个 ResetSubscriptions（）方法到 c1 ，将 someEvent 设置为null。我不知道这是否有任何看不见的后果。

Currently my solution is to add a ResetSubscriptions() method to c1 that sets someEvent to null. I don't know if this has any unseen consequences.

推荐答案

从类中可以设置（隐藏）变量到null空引用是有效表示空调用列表的规范方式。

From within the class, you can set the (hidden) variable to null. A null reference is the canonical way of representing an empty invocation list, effectively.

从类外，您不能这样做 - 事件基本上暴露订阅和取消订阅，就是这样。

From outside the class, you can't do this - events basically expose "subscribe" and "unsubscribe" and that's it.

值得注意的是，类似的事件正在做什么 - 他们正在创建一个变量和一个事件在同一时间。在类中，你最终引用变量。从外部你参考事件。

It's worth being aware of what field-like events are actually doing - they're creating a variable and an event at the same time. Within the class, you end up referencing the variable. From outside, you reference the event.

查看我的关于事件和代表的文章了解更多信息。

See my article on events and delegates for more information.

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