Question

我有一个简单的Windows服务，它运行并启动一个通过tcp / ip监听/接收心跳的线程。我很难找到在从tcp线程获取信息和使用该值来更新主线程中的信息之间进行同步的方法。

我尝试使用thread.sleep方法并继续循环它几次，同时等待线程的回复然后获取值，但该方法似乎有点不稳定，方法有时工作和有时不会。

那么在这两者之间进行同步的好方法是什么？基本上我想做的是启动监听tcp线程，获取特定值并更新主程序。

附件是接收函数和我用来启动线程的函数。 p.s：对于tcp / ip和c＃，我是一个完全noobie所以对代码或设计的任何部分的任何评论都非常受欢迎：）

public virtual void Receive()
        {
            string eventMessage = string.Empty;
            int bytesRcvd = 0;
            int totalBytesRcvd = 0;
            byte[] byteBuffer = new byte[maxBufferSize];
            NetworkStream listenStream;
            try
            {
                if (client.Connected)
                {
                    listenStream = client.GetStream();    
                }
                else
                {
                    return;
                }

                while (true)
                {                
                    //message that is slot in from the object will get sent here.
                    if (!string.IsNullOrEmpty(MessageToSend))
                    {
                        Send(MessageToSend);
                        MessageToSend = string.Empty;
                    }

                    // must convert it back and look for the delimiter, cannot wait for the three heartbeat to pass
                    string leftoverMsg = string.Empty;

                    bytesRcvd = listenStream.Read(byteBuffer, totalBytesRcvd, maxBufferSize - totalBytesRcvd);
                    totalBytesRcvd += bytesRcvd;

                    //if more than heart beat size, can process to see if it's a heartbeat and proceed to send
                    if (totalBytesRcvd > msgHeartbeatSize)
                    {
                        eventMessage = Encoding.ASCII.GetString(byteBuffer, 0, totalBytesRcvd);
                        ProcessMessage(eventMessage, ref leftoverMsg, ref totalBytesRcvd, ref byteBuffer);
                    }
                }
            }
            catch (ThreadAbortException thEx)
            {
                //do nothing as main thread has aborted and waiting to close
                logger.Info(Thread.CurrentThread.Name + " is stopped. ");
            }
            catch (Exception exce)
            {
                bIsActive = false;
                logger.Error(exce);
                CleanUp();
            }
            finally
            {
                logger.Info(String.Format("Thread {0} Exiting. ", Thread.CurrentThread.Name));
            }
        }

public virtual void StartReceivingThread()
        {
            Thread thrReceive = new Thread(Receive);
            try
            {
                if (!bIsActive && Connect())
                {
                    //NOTE: exception thrown by a thread can only be captured by that thread itself
                    //start a listen thread
                    //wait until heartbeat message is accepted

                    thrReceive.Name = "thr" + serviceType.Name;
                    thrReceive.Start();
                    bIsActive = true;

                    //wait to get the heartbeat message
                    for (int i = 0; i < maxRetry; i++)
                    {
                        Thread.Sleep(maxTimeOutValue);
                        if (bIsReceivingHeartbeat)
                            break;
                    }
                    //if nothing happens close the connection and try again
                    if (!bIsReceivingHeartbeat)
                    {
                        bIsActive = false;
                        CleanUp();
                        logger.Info("Closing  receiver thread - " + thrReceive.Name);
                    }
                    else
                    {
                        logger.Info("Starting  receiver thread - " + thrReceive.Name);
                    }
                }


            }
            catch(Exception ex)
            {
                logger.Error(ex);
            }
            //finally
            //{
            //    logger.Info("Exiting  receiver thread - " + thrReceive.Name);
            //}
        }

Answer 1

我认为bIsReceivingHeartbeat是该类的bool成员变量。如果在一个线程（接收器）中更改的值在另一个线程中不可见，则很可能是由于内存屏障。我在我的Java背景中说这个，但在.net中也很可能是这样。

尝试声明变量volatile或使用属性并使getter和setter同步：

private bool bIsReceivingHeartbeat;
public bool IsReceivingHeartbeat
{
    [MethodImpl(MethodImplOptions.Synchronized)]
    get { return bIsReceivingHeartbeat; }
    [MethodImpl(MethodImplOptions.Synchronized)]
    set { bIsReceivingHeartbeat = value; }
}

在调用代码中：

if (!IsReceivingHeartbeat) ....

我是从Java背景写的，但情况很可能类似

Answer 2

（看起来你也在refactormycode.com上发布了这段代码。）

无论如何，我建议使用一个由设置IsReceivingHeartbeat的代码脉冲的Event对象，而不是具有睡眠延迟的循环。请参阅MSDN中的ManualResetEvent和AutoResetEvent类。

如何在侦听/发送tcp客户端线程和主执行之间进行同步？

2 个答案: