如何从一个静态类引发自定义事件 [英] How to raise custom event from a Static Class

问题描述

我有一个静态类，我想提出一个事件作为类的静态方法中的一个try catch块的一部分。

I have a static class that I would like to raise an event as part of a try catch block within a static method of that class.

例如在这个方法我想提出在catch自定义事件。

For example in this method I would like to raise a custom event in the catch.

public static void saveMyMessage(String message)
{
    try
    {
        //Do Database stuff
    }
    catch (Exception e)
        {
              //Raise custom event here
        }
}

感谢您。

推荐答案

重要提示：非常小心的情况下订阅一个静态的事件。静态到静态是好的，但是从静态事件到一个实例句柄的订阅是一个伟大的（阅读：非常危险）的方式来保持该实例永远活着。 GC将看到该链接，除非你取消（或使用像一个WeakReference的）不会收集实例。

Important: be very careful about subscribing to a static event from instances. Static-to-static is fine, but a subscription from a static event to an instance handler is a great (read: very dangerous) way to keep that instance alive forever. GC will see the link, and will not collect the instance unless you unsubscribe (or use something like a WeakReference).

有关创建静态事件的模式是一样的isntance事件，只需用静态：

The pattern for creating static events is the same as isntance events, just with static:

public static event EventHandler SomeEvent;

为使生活更轻松（空重检查），这里有用的技巧是添加一个简单的处理程序：

To make life easier (re null checking), a useful trick here is to add a trivial handler:

public static event EventHandler SomeEvent = delegate {};

然后，你可以简单地调用它没有空检查：

Then you can simply invoke it without the null-check:

SomeEvent(null, EventArgs.Empty);

请注意，由于委托实例是不可改变的，和去引用是线程安全的，从来就没有在这里比赛状态，无需锁定...谁的一次，当我们去参考被调用订阅。

Note that because delegate instances are immutable, and de-referencing is thread-safe, there is never a race condition here, and no need to lock... who-ever is subscribed when we de-reference gets invoked.

（调整自己的事件，ARGS等）。
这招同样适用于实例的事件。

(adjust for your own event-args etc). This trick applies equally to instance events.

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