UdpClient在接收时如何停用

oioixiabings 2014-01-28 10:36:13

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Net;

using System.Net.Sockets;

using System.Text.RegularExpressions;





namespace UsbBoxUdpInterface

{

    public class UdpReceiver

    {

        const int c_ReceiveUdpEndPoint = 2112;

        bool done = false;

        UdpClient listener;

        System.Threading.Thread T1;



        public UdpReceiver()

        {

            T1 = new System.Threading.Thread(StartListener);

            T1.Start();

            

        }



        

        private void StartListener()

        {

            try

            {



                IPHostEntry ipHost = Dns.GetHostEntry("127.0.0.1");

                IPAddress ipAddress = ipHost.AddressList[1];

                IPEndPoint ipEndPoint = new IPEndPoint(ipAddress, c_ReceiveUdpEndPoint);

                listener = new UdpClient(ipEndPoint);



                while (!done)

                {

                    byte[] bytes = listener.Receive(ref ipEndPoint);[/color]                    string receiveString = Encoding.Default.GetString(bytes, 0, bytes.Length);

                    MessageEventArgs e = new MessageEventArgs();

                    e.Message = receiveString;

                    if (MessageRecieve != null && e.Message != "")

                    {

                        MessageRecieve(this, e);

                    }

                }



                listener.Close();

            }

            catch (Exception ex)

            {

                if (ex.GetType() != typeof(System.Threading.ThreadAbortException))

                {

                    System.Windows.Forms.MessageBox.Show("UdpReceiver StartListener()出错:" + ex.Message);

                }

            }



        }



        public event MessageReceivedEventHandle MessageRecieve;



        public void Close()

        {

            done = true;



            try

            {

                T1.Abort();

                listener.Close();

            }

            catch (Exception ex)

            {

                System.Windows.Forms.MessageBox.Show("UdpReceiver Close()出错:" + ex.Message);

            }

        }



    }



    public delegate void MessageReceivedEventHandle(object Sender, MessageEventArgs e);



    public class MessageEventArgs : EventArgs

    {

        public string Message;

    }

}

线程运行至byte[] bytes = listener.Receive(ref ipEndPoint);
处于接收状态。
代码采用：T1.Abort();
listener.Close();来中断listener.Receive状态，但会引发System.Threading.ThreadAbortException，有没有更好的方法来中断接收状态？

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oioixiabings 2014-01-30

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这段改一下：

   UdpClient udpClient = (UdpClient)((UdpState)(ar.AsyncState)).udpClient;
                IPEndPoint ipendPoint = (IPEndPoint)((UdpState)(ar.AsyncState)).ipEndPoint;
                Byte[] receiveBytes = udpClient.EndReceive(ar, ref ipendPoint);
                string receiveString = Encoding.Default.GetString(receiveBytes, 0, receiveBytes.Length);
                listener.Close();
                MessageEventArgs e = new MessageEventArgs();
                e.Message = receiveString;
                if (MessageRecieve != null && e.Message != "")
                {
                    MessageRecieve(this, e);
                }
                if (!StopReceive)
                {
                    StartListener();
                }
            }

否则偶尔会出“不能调用已使用的套接字”错误。

oioixiabings 2014-01-30

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感谢大家的回答！问题解决，现总结一下，以备他人参考。原来（见问题）因为程序退出后，不能正常退出此部分。任务管理器中无法退出程序，而发此贴。本段代码的作用是实现与其它系统之间的接口，通过UDP进行本机不同系统之间的互相通信。因不知对方系统什么时候发过来消息，所以需一直侦听。现作如下更改：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.Net.Sockets;
using System.Text.RegularExpressions;


namespace UsbBoxUdpInterface
{
    public class UdpReceiver
    {
        const int c_ReceiveUdpEndPoint = 2112;
        bool StopReceive = false;
        IPEndPoint ipEndPoint;
        UdpClient listener;

        public UdpReceiver()
        {
            IPHostEntry ipHost = Dns.GetHostEntry("127.0.0.1");
            IPAddress ipAddress = ipHost.AddressList[1];
            ipEndPoint = new IPEndPoint(ipAddress, c_ReceiveUdpEndPoint);
            StartListener();
        }


        private void StartListener()
        {
                listener = new UdpClient(ipEndPoint);
                UdpState myUdpState = new UdpState();
                myUdpState.udpClient = listener;
                myUdpState.ipEndPoint = ipEndPoint;
                listener.BeginReceive(new AsyncCallback(ReceiveCallback), myUdpState);
            }

        }

        void ReceiveCallback(IAsyncResult ar)
        {
            UdpClient udpClient = (UdpClient)((UdpState)(ar.AsyncState)).udpClient;
            IPEndPoint ipendPoint = (IPEndPoint)((UdpState)(ar.AsyncState)).ipEndPoint;
                Byte[] receiveBytes = udpClient.EndReceive(ar, ref ipendPoint);
                string receiveString = Encoding.Default.GetString(receiveBytes, 0, receiveBytes.Length);

                MessageEventArgs e = new MessageEventArgs();
                e.Message = receiveString;
                if (MessageRecieve != null && e.Message != "")
                {
                    MessageRecieve(this, e);
                    listener.Close();
                }
                if (!StopReceive)
                {
                    StartListener();
                }
        }

        public event MessageReceivedEventHandle MessageRecieve;

        public void Close()
        {
            StopReceive = true;
        }

    }

    public delegate void MessageReceivedEventHandle(object Sender, MessageEventArgs e);

    public class MessageEventArgs : EventArgs
    {
        public string Message;
    }

    public class UdpState
    {
        public UdpClient udpClient;
        public IPEndPoint ipEndPoint;
    }

}

结贴！谢谢！

oioixiabings 2014-01-29

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引用 1 楼 caozhy 的回复:

http://social.msdn.microsoft.com/Forums/en-US/fd22b27e-a46a-451c-bdb0-e3835c13df07/systemthreadingthreadabortexception

多谢版主的回答。如下改动

     private void StartListener()
        {
            try
            {

                IPHostEntry ipHost = Dns.GetHostEntry("127.0.0.1");
                IPAddress ipAddress = ipHost.AddressList[1];
                IPEndPoint ipEndPoint = new IPEndPoint(ipAddress, c_ReceiveUdpEndPoint);
                listener = new UdpClient(ipEndPoint);

                while (!done)
                {
                    byte[] bytes = listener.Receive(ref ipEndPoint);
                    string receiveString = Encoding.Default.GetString(bytes, 0, bytes.Length);
                    if (closeSignal.WaitOne(1000, false))
                        return;
                    if (closeSignal.WaitOne(0, false))
                        return;


                    MessageEventArgs e = new MessageEventArgs();
                    e.Message = receiveString;
                    if (MessageRecieve != null && e.Message != "")
                    {
                        MessageRecieve(this, e);
                    }


                }



                listener.Close();
            }
            catch (Exception ex)
            {
                if (ex.GetType() != typeof(System.Threading.ThreadAbortException))
                {
                    System.Windows.Forms.MessageBox.Show("UdpReceiver StartListener()出错:" + ex.Message);
                }
            }

        }
 public void Close()
        {
            done = true;

            try
            {
                closeSignal.Set();
                T1.Join();
                //T1.Abort();
                //listener.Close();//此名必须放在线程中断后执行，否则出错
            }
            catch (Exception ex)
            {
                System.Windows.Forms.MessageBox.Show("UdpReceiver Close()出错:" + ex.Message);
            }
        }

无法响应语句：if (closeSignal.WaitOne(0, false)) return; 麻烦再指导一下，谢谢！

oioixiabings 2014-01-29

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引用 4 楼 sp1234 的回复:

在编程中，不要胡乱写try......catch。胡乱写这个的人，一看就知道，很少测试，靠碰运气抄别人的代码“抄对了”而“写”代码。一个真正的程序，只需要在你发布产品的“最外层”去捕获异常、蒙混别人（好像代码不出现异常似地）就够了。没有必要用try....catch语句来蒙混自己、影响自己准确调试。

多谢指导，我会认真听取建议，谢谢！

Hassle 2014-01-29

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bool bExit = false 随便发一点什么，listener.Receive之后判断bExit == true也行

Hassle 2014-01-29

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没必要搞那么复杂，自己发送一个退出指令，listener.Receive之后判断是否退出。

以专业开发人员为伍 2014-01-29

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在编程中，不要胡乱写try......catch。胡乱写这个的人，一看就知道，很少测试，靠碰运气抄别人的代码“抄对了”而“写”代码。一个真正的程序，只需要在你发布产品的“最外层”去捕获异常、蒙混别人（好像代码不出现异常似地）就够了。没有必要用try....catch语句来蒙混自己、影响自己准确调试。

以专业开发人员为伍 2014-01-29