C＃的IAsyncResult为WaitAll [英] C# IAsyncResult WaitAll

问题描述

在一些我看到了下面的代码

In some of the implementations of WaitAll I have seen the following code

IAsyncResult result1 = Method.BeginInvoke(10, MyCallback, null)
IAsyncResult result2 = Method.BeginInvoke(20, MyCallback, null)
WaitHandle[] waitHandles = new WaitHandle[] { result1.AsyncWaitHandle, result2.AsyncWaitHandle};
WaitHandle.WaitAll(waitHandles)

这个问题似乎不是吗？什么是机会之前创建waitHandles阵列的调用完成？

Does this seem right ? What are the chances that before the waitHandles array is created one of the calls complete ?

问候，
Dhananjay

Regards, Dhananjay

推荐答案

对我来说很有意义。

// Begin invoking the first and second method, and give them a callback
IAsyncResult result1 = Method.BeginInvoke(10, MyCallback, null)
IAsyncResult result2 = Method.BeginInvoke(20, MyCallback, null)

// Any time past the point of invokation, MyCallback could be called.
// Get the wait handles of the async results, regardless of whether they have finished or not
WaitHandle[] waitHandles = new WaitHandle[] { result1.AsyncWaitHandle, result2.AsyncWaitHandle};

// Make sure to wait until the methods have finished.
// They could have finished immediately, and MyCallback could have already been called,
// but we will never get past this line unless they have finished.
WaitHandle.WaitAll(waitHandles)
// We may have waited on the function to finish, or they may have been done before we arrived at the previous line. Either way, they are done now.

你到底觉得奇怪？

What exactly do you find odd?

问什么是机会，是一个不好的迹象。机会是的可能会发生的，这意味着你将需要考虑程序需要做的，如果当你完成之前方法为WaitAll。

Asking "what are the chances" is a bad sign. The chances are it might happen which means you will need to account for what the program needs to do if and when the methods complete before you WaitAll.

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