void SendMsg(string toip, int port ){try{string message="发送内容";UdpClient udpclient = new UdpClient();IPEndPoint ipendpoint = new IPEndPoint(IPAddress.Parse(ip), port);              byte[] data = Encoding.Default.GetBytes(message);udpclient.Send(data, data.Length, ipendpoint);udpclient.Close();}catch (Exception ex){MessageBox.Show("UDP发送数据" + ex.ToString());}}

 public UdpService udp;a>实例化、初始化接收事件udp = new UdpService(fromip, 60000, "127.0.0.1", 60000);
udp.EvtGetValues+=new UdpService.GetRecevice(udp_EvtGetValues);b>启动UDPudp.TurnOn();c>停止UDPudp.TurnOff();d>接收事件处理void udp_EvtGetValues(byte[] ReceviceBuff){//string message = Encoding.UTF8.GetString(ReceviceBuff, 0, ReceviceBuff.Length);//可接收中文内容Encoding ei=Encoding.GetEncoding(936);string message = ei.GetString(ReceviceBuff, 0, ReceviceBuff.Length);if (message.Length > 0){// 处理接收逻辑
                }}

 public  class UdpService{#region 内部变量string devIP = "127.0.0.1";int devPort = 60000;UdpClient mySocket;string meIP = "127.0.0.1";int mePort = 60000;IPEndPoint RemotePoint;bool isRunning = false;bool isOpen = false;List<Thread> listThread = new List<Thread>();       string icId = "";string cardContent = "";byte[] cardContentBuf;#endregionpublic UdpService(string ServerIP, int ServerPort, string DevIP, int DevPort){this.meIP = ServerIP;this.mePort = ServerPort;this.devIP = DevIP;this.devPort = DevPort;           }#region   public void TurnOn(){try{if (isOpen) return;mySocket = new UdpClient(mePort);IPEndPoint ipLocalPoint = new IPEndPoint(IPAddress.Parse(meIP), mePort);RemotePoint = new IPEndPoint(IPAddress.Any, devPort);isRunning = true;Thread thread = new Thread(new ThreadStart(this.ReceiveHandle));thread.IsBackground = true;thread.Start();listThread.Add(thread);isOpen = true;}catch (Exception ex){isOpen = false;throw new Exception(ex.Message);}}public void TurnOff(){try{isOpen = false;isRunning = false;for (int i = 0; i < listThread.Count; i++){try{listThread[i].Abort();}catch (Exception) { }}if (mySocket != null){mySocket.Close();}}catch (Exception){}}public delegate void GetRecevice(byte[] ReceviceBuff);public event GetRecevice EvtGetValues;private void ReceiveHandle(){byte[] sendbuf = new byte[9];byte[] sendwritbuf = new byte[200];while (isRunning){try{if (mySocket == null || mySocket.Available < 1){Thread.Sleep(300);continue;}//接收UDP数据报，引用参数RemotePoint获得源地址  byte[] buf = mySocket.Receive(ref RemotePoint);if (devIP == null || devIP.Length < 1){devIP = RemotePoint.Address.ToString();devPort = RemotePoint.Port;}if (EvtGetValues != null){EvtGetValues(buf);}}catch (Exception){}}}#endregion}