如何知道超時或手動觸發器是否取消了任務？

Question

假設我有以下Start和Cancel事件處理程序。 我如何知道觸發取消的人是誰？

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();
    }

Answer 1

無論是否單擊了取消按鈕，都存儲在字段中：

bool hasUserCancelled = false;

並在開始之前重置此字段：

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

在取消按鈕單擊處理程序中設置它：

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

您想要的信息現在可以在catch中找到：

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