Question

我在用C＃编写的Windows服务中有一个TCP / IP客户端程序。截至目前一切正常。但我有一个查询，假设我的机器连接由于任何原因说机器不在网络或其他原因而关闭。我的应用程序将如何检测到它并尝试再次连接或重新获得连接？

以下是我在Windows服务中使用的代码：

private ManualResetEvent _shutdownEvent = new ManualResetEvent(false);
protected override void OnStart(string[] args)
    {
        _thread = new Thread(DoWork);
        _thread.Start();


         System.Timers.Timer _timer = new System.Timers.Timer(60 * 1000); // every 60 seconds
        _timer.Elapsed += new System.Timers.ElapsedEventHandler(timer_Elapsed);
        _timer.Start(); // <- important
    }

    private void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
    {

        if (client.Connected)
        {
            //Do nothing
        }
        else { 
           //close the thread and again start.
            try
            {
                using (StreamWriter streamWriter = File.AppendText(textfileSaveLocation))
                {
                    streamWriter.WriteLine("Disconnected!!!!");
                }
            }
            catch (Exception Ex)
            {
                Ex.Message.ToString();
            }

            _shutdownEvent.Set();
            _thread.Start();

        }         
     }

    private void DoWork()
    {
        while (!_shutdownEvent.WaitOne(0))
        {
            TcpClient client = new TcpClient();
            string data= "";
            fileSaveLocation = location;

            try
            {
                client.Connect(new IPEndPoint(IPAddress.Parse(ip), port));
            }
            catch (Exception ex)
            {
                // Log the error here.
                client.Close();
                continue;
            }

            try
            {
                using (NetworkStream stream = client.GetStream())
                {
                    byte[] notify = Encoding.ASCII.GetBytes("Hello");
                    stream.Write(notify, 0, notify.Length);

                    byte[] data = new byte[1024];
                    while (!_shutdownEvent.WaitOne(0))
                    {
                        int numBytesRead = stream.Read(data, 0, data.Length);
                        if (numBytesRead > 0)
                        {
                            data= Encoding.ASCII.GetString(data, 0, numBytesRead);
                        }

                    }
                }
            }
            catch (Exception ex)
            {
                // Log the error here.
                client.Close();
            }
        }
    }

    protected override void OnStop()
    {
        _shutdownEvent.Set();  // trigger the thread to stop
        _thread.Join();        // wait for thread to stop
    }

请帮帮我。任何建议都会有所帮助。谢谢..

Answer 1

连接关闭或断开连接时，

TcpClient不会收到通知。您可以手动检查TcpClient是否在每个特定时期内连接，如 -

if(tcpClient.Connected)
{
     //code
}
else
{
     //renew connection
}

或者，您必须根据需要处理Catch块中的Exception。

如何检测断开的TCP连接并再次连接

1 个答案: