C# UDP通讯的问题,急

Question

前台是指客户端 后台服务器？
最好把你新建线程的处理函数贴出来，估计是那个出了问题。
从你的描述来看，服务器可以收到客户端的签到，所以通信没有问题，然后服务器向签到了的IP和端口号发包，
如果客户端的新线程要接受到这些报文，必须在原来签到的那个套接字上接收。所以你需要向新线程传递这个套接字

Answer 1

  public void ListenPort()
        {
            IPEndPoint tempEnd = new IPEndPoint(IPAddress.Any, 2525);
            while (runing)
            {
                Application.DoEvents();
                try
                {
                    byte[] recb = listen.Receive(ref tempEnd);                    // 检查所接收到的信息and处理之
                    checkMessage(recb);
                }
                catch (Exception e)
                {
                    MessageBox.Show("出现错误：" + e.Message.ToString());
                    break;
                }            }
            listen.Close();
            runing = false;
        }public void checkMessage(byte[] recbb)
        {
            RecordsetOperate rso = new RecordsetOperate();
            sendData recData = BytesToStruct(recbb);
            romeName = recData.computerName;
            romeIP = recData.fromIP;
            romeCon = recData.content;
            switch (recData.commandNo)
            {
                case 0x00: //刷新
                    if (recData.toIP.Equals(myIP))
                    {
                        //在我的同事和成员里 搜索 是否有 此人在线 有将要显示 他的状态  为在线
                        //if (box.FindString(recData.fromIP.ToString() + "  " + recData.computerName) <= 0)
                        //    box.Items.Add(recData.fromIP.ToString() + "  " + recData.computerName);
                        //online.Text = "在线用户：" + (box.Items.Count - 1) + "人";
                        //比较 
                        string ip = recData.fromIP.ToString();
                        string StrAccount = "";
                        string userName = "";
                        string NickName = "";                        if (rso.R_returnUserNameandNumber(ip, ref StrAccount, ref userName, ref NickName) == false)
                        {
                            //没有此用户 添加此用户
                            rso.L_InserColleague(StrUserNumber, "我的同事", StrAccount);
                        }                    }
                    else if (recData.fromIP.Equals(recData.toIP))
                    {
                        //从其他机器发送过来的刷新请求
                        //返回自己的信息
                        mySendData.commandNo = 0x00;
                        mySendData.toIP = recData.toIP;
                        mySendData.content = "上线提示";
                        byte[] sendb = StructToBytes(mySendData);
                        SendPack(sendb);
                        //如果不存在则添加该用户
                        //if (box.FindString(recData.fromIP.ToString() + "  " + recData.computerName) <= 0)
                        //    box.Items.Add(recData.fromIP.ToString() + "  " + recData.computerName);
                    }
                    break;
                case 0x01: //发言
                    if (recData.toIP.Equals(myIP) && !isfile)
                    {
                        // recData.fromIP
                        //通过IP 获得 用户帐号，通过用户帐号使 用户的 图表 颤动
                        string StrAccount = "";
                        string userName = "";
                        string NickName = "";                        if (rso.R_returnUserNameandNumber(recData.fromIP.ToString(), ref StrAccount, ref userName, ref NickName) == true)
                        {
                            if (MessageBox.Show(NickName + "，来短信了。请注意察收。", "新的短信", MessageBoxButtons.YesNo) == DialogResult.Yes)
                            {
                                #region 关闭监听
                                runing = false;
                                UdpClient mm = new UdpClient();
                                IPEndPoint tempIPEnd = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 2525);
                                mySendData.commandNo = 0;
                                mySendData.fromIP = myIP;
                                mySendData.computerName = myName;
                                mySendData.toIP = myIP;
                                mySendData.content = "上线提示";
                                byte[] sendb = StructToBytes(mySendData);
                                mm.Send(sendb, sendb.Length, tempIPEnd);
                                #endregion
                                #region 显示窗体
                                Frm_TalkingAndTransfersFile fat = new Frm_TalkingAndTransfersFile();                                fat.ToIp = recData.fromIP.ToString();
                                Frm_TalkingAndTransfersFile.StrNeiRong = DateTime.Now.ToShortTimeString() + ":" + NickName + "/" + recData.content;
                                fat.ShowDialog();
                                #endregion
                                #region  打开监听
                                Thread myThread = new Thread(new ThreadStart(this.ListenPort));
                                myThread.IsBackground = false;
                                myThread.Start();
                                #endregion
                            }
                            else
                            {
                                break;
                            }
                        }
                    }
                    break;
                case 0x02: //请求传文件
                    if (recData.toIP.Equals(myIP))
                    {//准备接收文件
                        romeFileName = romeCon.Split('+')[0];
                        romeFilel = romeCon.Split('+')[1];
                        readyRecFile();
                    }
                    break;
                case 0x03://传文件
                    if (recData.toIP.Equals(myIP))
                    {//传送文件
                        // Thread mysend = new Thread(new ThreadStart(sendFile));
                        //mysend.Start();
                    }
                    break;
                case 0x09: //确认包
                    if (recData.toIP.Equals(myIP))
                        MessageBox.Show("信息来自：" + recData.computerName + "(" + recData.fromIP.ToString() + ")\r\n" + recData.content, "消息");
                    break;
            }        } 我想 楼主 看看 这个 接收 解析 能够 了解点问题  这个我是做的 一个项目