C# C/S 客户端不能正确接收服务器发来的第二次数据
在登陆过程中客户端新建了个线程来和服务器会话
 private void 登陆_Load(object sender, EventArgs e)
        {
            contactWithServer = new ContactWithServer(this, user);
            Thread clientcontactserverThread = new Thread(new ThreadStart(contactWithServer.contact));
            clientcontactserverThread.Start();           
        }
客户端接收程序
  public void contact()
     {
        //receiveIpep = new IPEndPoint(IPAddress.Parse(serverIP), 8888);
        ////sendIpep = new IPEndPoint(IPAddress.Parse(serverIP), 6666);       //服务器端接收端口
        //udpReceiveClient = new UdpClient(receiveIpep);
        receiveIpep = null;       
        try
        {
            udpReceiveClient = new UdpClient(8888);
            while (true)
            {
                MessageBox.Show("where"); 
                byte[] data = udpReceiveClient.Receive(ref receiveIpep);
                if (data.Length < 20)                       //只有命令
                    commandStr = Encoding.ASCII.GetString(data);
                else                                       //既有命令又有数据
                {