CODEWITHSUNDEEP
c#-4.0asynchronousasync-awaitcancellationcancellationtokensource
amiry jd
amiry jd

Reputation: 27585

Error: The operation was canceled

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());

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?

Upvotes: 3

Views: 19242

Answers (1)

G. Stoynev
G. Stoynev

Reputation: 7783

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());

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.

Upvotes: 1

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