高手帮忙！！！

高手帮我看下哪里有问题，
另外我重新调用connserver()方法的时候，窗体就会关闭这是为什么啊
 private void Form3_Load(object sender, EventArgs e)
        {
                   connserver();
                     
        } public void connserver()
        {
            TCPConnection conn = new TCPConnection(_ipAddr, _port);
            TcpClient _tcpc = conn.Connect();
            try
            {
                if (_tcpc == null)
                {                    timer2.Start();
                    txtserver.AppendText("没有链接到服务器，你讲不能正常接收服务器的及时消息！系统将在一分钟后重新链接！\r\n\r\n");                }
                else
                {
                    txtserver.AppendText("已成功链接到服务器，正在监听.....\r\n\r\n");                    NetworkStream netstream = _tcpc.GetStream();
                    //向服务器发送用户名以确认身份
                    netstream.Write(Encoding.Unicode.GetBytes(_username), 0, Encoding.Unicode.GetBytes(_username).Length);
                                        byte[] buffer = new byte[50];
                    netstream.Read(buffer, 0, buffer.Length);
                    _nws = netstream;
                                        _receiveThread = new Thread(new ThreadStart(ReceiveMsg));   //创建线程
                    _receiveThread.Start();  //线程开始                }
            }
            catch (Exception ce)
            {
                MessageBox.Show("出现错异常了！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
        }
        
       private void ReceiveMsg()
         {
             while (true)
             {
                 try
                 {
                     byte[] packet = new byte[_maxPacket];
                     _nws.Read(packet, 0, packet.Length);
                     string dis = Encoding.Unicode.GetString(packet);                     txtserver.AppendText(dis);
                 }
                 catch
                 {                     MessageBox.Show("数据接收失败");
                  }
             }
        }