C#线程安全使用（五）

CancellationToken的多种应用

这是线程安全的最后一篇了，主要介绍CancellationToken的多种应用。

1,ThreadPool直接启动线程，传递CancellationToken。

2,Task启动线程，传递CancellationToken。Task传递方式分为两种，一种通过Task的参数进行传递，另一种通过向线程内传递对象的方式传递CancellationToken。

3,CancellationToken的回调函数应用。

话不多说，请看代码。

class Program
  {
      static void Main(string[] args)
      {
          Console.WriteLine("当前线程{0},当前状态{1}", Thread.CurrentThread.GetHashCode(), Thread.CurrentThread.ThreadState);
          //使用线程池创建线程，然后取消线程
          CancelWithThreadPoolMiniSnippet();
      }
      static CancellationTokenSource cts = new CancellationTokenSource();
      static CancellationToken token = cts.Token;
      static void CancelWithThreadPoolMiniSnippet()
      {
          Console.WriteLine("当前线程{0},当前状态{1}", Thread.CurrentThread.GetHashCode(), Thread.CurrentThread.ThreadState);
 
          #region 使用QueueUserWorkItem的构造函数，传递cts.Token,但我不喜欢这个模式 跟踪不了状态
          //ThreadPool.QueueUserWorkItem(new WaitCallback(DoSomeWork), ctn);
          #endregion
 
          #region 使用传递参数的模式 传递CancellationToken，这里的cts.Token是作为Action的参数传递的
          //var action = new Action<object>(DoSomeWork);
          //Task t = new Task(action, ctn);
          //t.Start();
          //Console.WriteLine("开始，当前线程{0},当前状态{1}", t.GetHashCode(), t.Status);
          #endregion
 
          #region 使用Task的构造函数，传递cts.Token,但CancellationTokenSource要弄成全局变量，否则方法找不到，就取消不了。
          //Task t = new Task(Work, cts.Token);
          //t.Start();
          #endregion
 
          #region 注册回调函数，当CancellationTokenSource.Cancel()执行后，调用回调函数 
          token.Register(CallBack, true);  //注册回调函数
          Task t = new Task(Work);
          t.Start();
          #endregion
 
          Thread.SpinWait(5000000);
           
          cts.Cancel();
          Console.WriteLine("结束，当前线程{0},当前状态{1}", t.GetHashCode(), t.Status);
          Console.Read();
      }
 
      
      static void DoSomeWork(object obj)
      {
          CancellationToken token = (CancellationToken)obj;
          for (int i = 0; i < 100000; i++)
          {
              Console.WriteLine(i);
              // Simulating work.
              //Thread.SpinWait(5000000);
 
              if (token.IsCancellationRequested)
              {
                  
                  break;
              }
          }
      }
 
 
      static void Work()
      {
          
          for (int i = 0; i < 100000; i++)
          {
              Console.WriteLine(i);
              if (token.IsCancellationRequested)
              {
 
                  break;
              }
          }
      }
 
      static void CallBack()
      {
           
          Console.WriteLine("I'm call back!"   );
      }
  }