How do I know whether a Task is canceled by a timeout or a manual trigger?

async-await, c#, cancellationtokensource, task-parallel-library

Solution

Store in a field whether the cancel-button was clicked or not:

bool hasUserCancelled = false;

And reset this field before you start:

        hasUserCancelled = false;
        cts = new CancellationTokenSource();
        cts.CancelAfter(5000);

Set it in the cancel-button click handler:

private void OnCancelClick(object sender, RoutedEventArgs e)
{
    hasUserCancelled = true;
    cts.Cancel();
    cts.Dispose();
}

The information that you wanted is now available in the catch:

    catch (TaskCanceledException taskCanceledException)
    {
        Debug.WriteLine(new { hasUserCancelled });
    }

Problem

Say I have the following Start and Cancel event handlers. How do I know who was the one who triggered the cancellation? ``` private CancellationTokenSource cts; private async void OnStartClick(object sender, RoutedEventArgs e) { try { cts = new CancellationTokenSource(); cts.CancelAfter(5000); await Task.Delay(10000,cts.Token); } catch (TaskCanceledException taskCanceledException) { ??? How do i know who canceled the task here ??? } } private void OnCancelClick(object sender, RoutedEventArgs e) { cts.Cancel(); cts.Dispose(); } ```

Original source