/// <summary>
        /// 启动监听，轮询监听客户机请求并将客户端套接字存入转发表
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param> 
        private void Listen()
        {
            IPAddress _ip = IPAddress.Any;
            Socket newsoc = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            newsoc.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
            IPEndPoint locaEp = new IPEndPoint(IPAddress.Any, _port);//建立连接
            try
            {
                newsoc.Bind(locaEp);
                newsoc.Listen(100);
                newsoc.BeginAccept(new AsyncCallback(onCall), newsoc);//异步监听回调
            }
            catch (Exception ex)
            {
                DAL.Log.Write(DateTime.Now.ToString() + ex.ToString() + "\r\n\r\n");
            }
        }

        /// <summary>
        /// 监听回调
        /// </summary>
        /// <param name="ar"></param>
        private void onCall(IAsyncResult ar)
        {
            try
            {
                Socket serverSoc = (Socket)ar.AsyncState;
                Socket clent = serverSoc.EndAccept(ar);
                byte[] comes = new byte[1024];
                EndPoint enp = clent.RemoteEndPoint;
                clent.Send(comes, comes.Length, 0);
                _transmit_tb.Add(clent.RemoteEndPoint, null);
                serverSoc.BeginAccept(new AsyncCallback(onCall), serverSoc);
                while (true)
                {
                    byte[] buffer = new byte[1024];
                    int re = clent.Receive(comes);
                    clent.Send(Encoding.ASCII.GetBytes("ok!"));
                    string msg = Encoding.UTF8.GetString(comes, 0, re);
                    string ip = clent.RemoteEndPoint.ToString();
                    if (msg.Length == 0)
                    {
                        _transmit_tb.Remove(clent.RemoteEndPoint);
                        _receviccethread.Interrupt();
                        _receviccethread.Abort();
                        break;