错误：该操作被取消 [英] Error: The operation was canceled

问题描述

我使用这个code段做一个取消标记一个异步查询：

I'm using this code snippet to do an async query with a cancellation token:

var _client = new HttpClient( /* some setthngs */ );

_client.GetAsync(someUrl, cancellationToken).ContinueWith(gettingTask => {
    cancellationToken.ThrowIfCancellationRequested();
    SomeStuffToDO();
    }, TaskScheduler.FromCurrentSynchronizationContext());
}, TaskScheduler.FromCurrentSynchronizationContext());

但是，当运行被取消， cancellationToken.ThrowIfCancellationRequested（）; 抛出异常。我知道，这条线应该到这个东西。但是，在开发环境中，异常导致Visual Studio中休息。我怎样才能避免这种情况？

But, when operation get cancelled, cancellationToken.ThrowIfCancellationRequested(); throws an exception. I know that this line should to this stuff. But, in developing environment, the exception causes the visual studio to a break. How can I avoid this?

推荐答案

您需要将拉姆达内处理，就像这样：

You need to handle within the lambda, like this:

var _client = new HttpClient( /* some setthngs */ );

_client.GetAsync(someUrl, cancellationToken).ContinueWith(gettingTask => {
    try {
     cancellationToken.ThrowIfCancellationRequested();
     SomeStuffToDO();
    }
    catch (...) { ... }
    finaly { ... }
    }, TaskScheduler.FromCurrentSynchronizationContext());
}, TaskScheduler.FromCurrentSynchronizationContext());

但 _client.GetAsync（someUrl，的CancellationToken）也有可能抛出异常注销，所以你需要用的电话（或在其包含的方法等待）与一试-catch。

But _client.GetAsync(someUrl, cancellationToken) might also throw cancellation exception, so you need to wrap that call (or where its containing method is awaited) with a try-catch.

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