我創(chuàng)建了一個(gè)簡(jiǎn)單的 .NET Framework 4.7.2 WPF 應(yīng)用程序，其中包含兩個(gè)控件 - 一個(gè)文本框和一個(gè)按鈕。這是我的代碼：private async void StartTest_Click(object sender, RoutedEventArgs e){ Output.Clear(); var cancellationTokenSource = new CancellationTokenSource(); // Fire and forget Task.Run(async () => { try { await Task.Delay(TimeSpan.FromMinutes(1), cancellationTokenSource.Token); } catch (OperationCanceledException) { Task.Delay(TimeSpan.FromSeconds(3)).Wait(); Print("Task delay has been cancelled."); } }); await Task.Delay(TimeSpan.FromSeconds(1)); await Task.Run(() => { Print("Before cancellation."); cancellationTokenSource.Cancel(); Print("After cancellation."); });}private void Print(string message){ var threadId = Thread.CurrentThread.ManagedThreadId; var time = DateTime.Now.ToString("HH:mm:ss.ffff"); Dispatcher.Invoke(() => { Output.AppendText($"{ time } [{ threadId }] { message }\n"); });}按下按鈕后，我在文本框中StartTest看到以下結(jié)果：Output12:05:54.1508 [7] Before cancellation.12:05:57.2431 [7] Task delay has been cancelled.12:05:57.2440 [7] After cancellation.我的問(wèn)題是為什么[7] Task delay has been cancelled.在請(qǐng)求令牌取消的同一線程中執(zhí)行？我希望看到的是[7] Before cancellation.然后是[7] After cancellation.然后Task delay has been cancelled.?；蛘咧辽賂ask delay has been cancelled.在另一個(gè)線程中執(zhí)行。請(qǐng)注意，如果我cancellationTokenSource.Cancel()從主線程執(zhí)行，那么輸出看起來(lái)像預(yù)期的那樣：12:06:59.5583 [1] Before cancellation.12:06:59.5603 [1] After cancellation.12:07:02.5998 [5] Task delay has been cancelled.
意外的任務(wù)取消行為
哆啦的時(shí)光機(jī)
2022-11-21 15:46:34
