如何使异步方法返回一个值？ [英] How to make an Asynchronous Method return a value?

问题描述

我知道如何使异步方法，但说我有，做了很多工作，然后返回一个布尔值的方法？

I know how to make Async methods but say I have a method that does a lot of work then returns a boolean value?

如何在回调返回布尔值？

How do I return the boolean value on the callback?

澄清

public bool Foo(){
    Thread.Sleep(100000); // Do work
    return true;
}

我希望能够使这个异步

I want to be able to make this asynchronous.

推荐答案

有这样做的几种方法......最简单的就是有异步方法也做了后续的操作。另一种流行的做法是在回调，即通过。

There are a few ways of doing that... the simplest is to have the async method also do the follow-on operation. Another popular approach is to pass in a callback, i.e.

void RunFooAsync(..., Action<bool> callback) {
     // do some stuff
     bool result = ...

     if(callback != null) callback(result);
}

另一种方法是提高一个事件（其结果在事件ARGS数据）时，异步操作完成

Another approach would be to raise an event (with the result in the event-args data) when the async operation is complete.

此外，如果您使用的是第三方物流，可以使用 ContinueWith ：

Also, if you are using the TPL, you can use ContinueWith:

Task<bool> outerTask = ...;
outerTask.ContinueWith(task =>
{
    bool result = task.Result;
    // do something with that
});

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