远程主机强迫关闭了一个现有的连接

服务端

        public static ManualResetEvent allDone = new ManualResetEvent(false);

        private Thread yth;

        private bool listenerRun = true;

        Socket listener;

        private const int maxsocket = 10000;

        int port = 54321;

        private void buttonStart_Click(object sender, EventArgs e)

        {

            listenerRun = true;

            yth = new Thread(new ThreadStart(ListenClient));

            yth.IsBackground = true;

            yth.Start();

            this.buttonStart.Enabled = false;

            this.buttonStop.Enabled = true;

        }

        public void ListenClient()

        {

            while (listenerRun)

            {

                allDone.Reset();

                listener.BeginAccept(new AsyncCallback(AcceptCallBack), listener);

                allDone.WaitOne();

            }

        }

        private void AcceptCallBack(IAsyncResult ar)

        {

            try

            {

                allDone.Set();

                Socket sok = (Socket)ar.AsyncState;

                Socket client = sok.EndAccept(ar);

                StateObject state = new StateObject();

                state.workSocket = client;

                if(client.Available>0)

                client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReadCallBack), state);



            }

            catch (Exception Err)

            {

                throw Err;

            }

        }

        public class StateObject

        {

            public Socket workSocket = null;

            public const int BufferSize = 1024;

            public byte[] buffer = new byte[BufferSize];

        }

        System.Net.IPAddress[] addressList;

        private void Form1_Load(object sender, EventArgs e)

        {

            this.buttonStop.Enabled = false;

            dtu.Columns.Add("hostname", Type.GetType("System.String"));

            dtu.Columns.Add("remoteip", Type.GetType("System.String"));

            dtu.Columns.Add("activetime", Type.GetType("System.DateTime"));

            this.dataGridView1.DataSource = dtu;

            addressList = Dns.GetHostEntry(Dns.GetHostName()).AddressList;

            IPAddress ipaddress = addressList[0];

            IPEndPoint ipendpoint = new IPEndPoint(ipaddress, port);

            listener = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

            listener.Bind(ipendpoint);

            listener.Listen(50);

        }



        private void buttonStop_Click(object sender, EventArgs e)

        {

            this.buttonStop.Enabled = false;

            this.buttonStart.Enabled = true;

            listenerRun = false;

        }

        private void ReadCallBack(IAsyncResult ar)

        {

            try

            {

                StateObject state = (StateObject)ar.AsyncState;

                Socket hander = state.workSocket;

                int readbyte = hander.EndReceive(ar);

                if (readbyte > 0)

                {

                   

                    string strmsg = Encoding.UTF8.GetString(state.buffer, 0, readbyte);

                    hander.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReadCallBack), state);

                }



            }

            catch (Exception Err)

            {

                throw Err;

            }

        }

客户端

   private Socket sok;

        private IPAddress ipaddress;

        private IPEndPoint ipendpoint;

        int port = 54321;

        private void button1_Click(object sender, EventArgs e)

        {

            Thread th = new Thread(new ThreadStart(Get_TEst));

            th.IsBackground = true;

            th.Start();

            this.buttonStart.Enabled = false;

        }

        private void Get_TEst()

        {

            try

            {

                ipaddress = IPAddress.Parse("192.168.1.102");

             

                ipendpoint = new IPEndPoint(ipaddress, port);

                sok = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

                sok.Connect(ipendpoint);



                while (true)

                {

                    byte[] sendbyte = new byte[1024];

                    string str = hostName + "|" + clientIP;

                    //string str = " ";

                    sendbyte = Encoding.UTF8.GetBytes(str);

                    sok.Send(sendbyte);

                    Thread.Sleep(5000);

                }

            }

            catch (Exception Err)

            {

                throw Err;

            }

        }

        string clientIP = "";

        string hostName = "";

        private void Form1_Load(object sender, EventArgs e)

        {

            clientIP = Dns.GetHostEntry(Dns.GetHostName()).AddressList[0].ToString();

            hostName = Dns.GetHostName();

        }

当客户端退出的时候 出现错“远程主机强迫关闭了一个现有的连接”
经过调试 错误出现在这个函数里
private void ReadCallBack(IAsyncResult ar)
{
try
{
StateObject state = (StateObject)ar.AsyncState;
Socket hander = state.workSocket;
int readbyte = hander.EndReceive(ar);
if (readbyte > 0)
{

string strmsg = Encoding.UTF8.GetString(state.buffer, 0, readbyte);
hander.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReadCallBack), state);
}

}
catch (Exception Err)
{
throw Err;
}
}
请教怎么解决这个问题啊？