c# - 如何在 C# 中停止正在运行的任务

Question

我有一个正在运行的任务，需要制作一个用户可以随时停止正在运行的任务的功能。我试着 token.Cancel();但还是没用。

这是我的代码:

var task = new Task(new Action(Method), tokenSource2.Token);
 var cToken = tokenSource2.Token;
cToken.Register(() => cancelNotification());

// code to stop the running task .. button click event

 if (tokenSource2 != null)
            {

                tokenSource2.Cancel();


            }

Answer 1

我相信要使取消 token 起作用，作为任务主体调用的方法需要接受取消 token 并不断检查它是否已在每个逻辑步骤之间被取消。 See here for more details .

此示例摘自该文档并概述了如何检查取消 token 的状态。

using System;
using System.Threading;

public class Example
{
   public static void Main()
   {
      // Create the token source.
      CancellationTokenSource cts = new CancellationTokenSource();

      // Pass the token to the cancelable operation.
      ThreadPool.QueueUserWorkItem(new WaitCallback(DoSomeWork), cts.Token);
      Thread.Sleep(2500);

      // Request cancellation.
      cts.Cancel();
      Console.WriteLine("Cancellation set in token source...");
      Thread.Sleep(2500);
      // Cancellation should have happened, so call Dispose.
      cts.Dispose();
   }

   // Thread 2: The listener
   static void DoSomeWork(object obj)
   {
      CancellationToken token = (CancellationToken)obj;

      for (int i = 0; i < 100000; i++) {
         if (token.IsCancellationRequested)
         {
            Console.WriteLine("In iteration {0}, cancellation has been requested...",
                              i + 1);
            // Perform cleanup if necessary.
            //...
            // Terminate the operation.
            break;
         }
         // Simulate some work.
         Thread.SpinWait(500000);
      }
   }
}
// The example displays output like the following:
//       Cancellation set in token source...
//       In iteration 1430, cancellation has been requested...