c# - winform 中的线程 - Compact .NET Framework 3.5

Question

我在启动实时监控的函数中有一个线程，它基本上打开串口并不断从串口读取数据。但是，如果我需要终止这个线程，我应该怎么做呢？因为如果我不终止打开特定串口和读取数据的运行线程。当我关闭它并再次调用该函数时。同一个串口打不开。我怀疑串行端口没有正确关闭并且仍在单独的线程中运行。所以我想我必须终止那个线程，以便下次再次打开同一个串行端口。有谁知道如何实现这一点？

我看到一些论坛说 Thread.Abort() 使用起来很危险。它应该只在最后的手段中使用。

感谢您的帮助。

查尔斯

Answer 1

通常，您设计在后台线程中运行的方法来监听取消请求。这可以像 bool 值一样简单:

//this simply provides a synchronized reference wrapper for the Boolean,
//and prevents trying to "un-cancel"
public class ThreadStatus
{
   private bool cancelled;

   private object syncObj = new Object();

   public void Cancel() {lock(syncObj){cancelled = true;}}

   public bool IsCancelPending{get{lock(syncObj){return cancelled;}}}
}

public void RunListener(object status)
{
   var threadStatus = (ThreadStatus)status;

   var listener = new SerialPort("COM1");

   listener.Open();

   //this will loop until we cancel it, the port closes, 
   //or DoSomethingWithData indicates we should get out
   while(!status.IsCancelPending 
         && listener.IsOpen 
         && DoSomethingWithData(listener.ReadExisting())
      Thread.Yield(); //avoid burning the CPU when there isn't anything for this thread

   listener.Dispose();
}

...

Thread backgroundThread = new Thread(RunListener);
ThreadStatus status = new ThreadStatus();
backgroundThread.Start(status);

...

//when you need to get out...
//signal the thread to stop looping
status.Cancel();
//and block this thread until the background thread ends normally.
backgroundThread.Join()