button_click下的代码如下
 try
            {
                int port = Convert.ToInt32(txtPort.Text.Trim());
                string host = txtIPaddress.Text.Trim();
                 IPAddress ip = IPAddress.Parse(host);
                //IPAddress ipp = new IPAddress("127.0.0.1");
                 IPEndPoint ipe = new IPEndPoint(ip, port);
                Socket c = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);//创建Socket
                c.Connect(ipe);//连接到服务器
                 pictureBox1.Visible = true;
                 pictureBox2.Visible = false;
                 string sendStr = "PM01";
                byte[] bs = Encoding.ASCII.GetBytes(sendStr);                 
                 c.Send(bs, bs.Length, 0);                               string recvStr = "";
                byte[] recvBytes = new byte[1024];
                int bytes;
                bytes = c.Receive(recvBytes, recvBytes.Length, 0);//从服务器端接受返回信息
                recvStr += Encoding.ASCII.GetString(recvBytes, 0, bytes);
                txtRec.Text = recvStr + Environment.NewLine;
                             
                 
                           c.Close();
             }
            catch (ArgumentNullException ex)
            {
                 Console.WriteLine("argumentNullException: {0}", ex);
             }
            catch (SocketException ex)
            {
                 Console.WriteLine("SocketException:{0}", ex);
             }
             Console.WriteLine("Press Enter to Exit");
         }
点击button后会接受服务器端的数据,随后服务器端发数据,就接受不到了,当再次点击button时才会接收数据,为什么???请高手指导