基于Socket的UDP发包程序

UDP(User Datagram Protocol,用户数据报协议)是在互联网中常用的传输层协议，该协议提供了向另一用户程序发送的消息的最简便的协议机制。与TCP一样，其默认的下层协议是IP.UDP是面向操作的，不提供提交和复制保护，因此不能保证数据的可靠性传输。UDP一般用在可靠性较高的局域网中。

.NET 下可使用Socket 类编写基于UDP的网络程序，只要在创建Socket时将构造函数函数的第三个参数选为枚举值ProtocolType.Udp即可.此外，.NET的System.Net.Sockets命名空间下还有一个UdpClient类，可专门用于UDP的网络编程。-----摘自< C#.NET 框架高级编程技术案例教程  郭文夷等 P163>

第一种，使用Socket类

  IPEndPoint ip = new IPEndPoint(IPAddress.Parse(txtIP.Text), int.Parse(txtPort.Text));
             Socket  serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
             serverSocket.Bind(ip);

第二种，使用UdpClient类

  IPAddress address = IPAddress.Parse(txtLocalIp.Text);
             int port = Int32.Parse(txtLocalPort.Text);
             IPEndPoint endPoint = new IPEndPoint(address, port);
             UdpClient udpClient = new UdpClient(endPoint);

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本文主要采用第一种，基于Socket编写一个Udp发包程序。服务器端不断发包，客户端根据接收到的点数据在窗体上绘制点，效果如下所示：

一.服务器端

1.创建一个Socket对象，绑定服务器端Ip和端口号。

2.创建一个线程用户获取客户机的Ip和端口号。大致是这样的，客户机连接到服务器，同时发送一个"你好"的消息，服务器端这样就可以获取到客户机的Ip和端口。

   private void btnStart_Click(object sender, EventArgs e)
         {
             if (serverSocket != null)
             {
                 return;
             }
             IPEndPoint ip = new IPEndPoint(IPAddress.Parse(txtIP.Text), int.Parse(txtPort.Text));
             serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
             serverSocket.Bind(ip);

             AppendTextToTxtLog(string.Format("服务器端是{0},正在等待客户端的连接",ip.ToString()));
             Thread thread = new Thread(ReceiveData);
             thread.IsBackground = true;
             thread.Start();

         }

3.发送数据

  private void SendData()
         {
             byte[] data = new byte[ * ];
             int j = ;
             Random r = new Random();
             while (j >)
             {
                 j--;
                 int x = r.Next();
                 int y = r.Next();
                 string msg = x.ToString() +","+ y.ToString();
                 data = Encoding.Default.GetBytes(msg);
                 for (int k = ; k < RemoteList.Count; k++)
                 {
                     int i = serverSocket.SendTo(data, data.Length, SocketFlags.None,RemoteList[k]);
                     AppendTextToTxtLog(string.Format("发送给客户端{0}的消息是{1}", RemoteList[k].ToString(), msg));
                 }
             }
         }

客户端

1.连接到服务器端

    private void btnConnected_Click(object sender, EventArgs e)
         {
             byte[] data = new byte[];

             IPEndPoint ip = new IPEndPoint(IPAddress.Parse("192.168.10.179"), );
             ServerSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
             string welcome = "你好!";
             data = Encoding.Default.GetBytes(welcome);
             ServerSocket.SendTo(data, data.Length, SocketFlags.None, ip);
             Thread thread = new Thread(ReceiveData);
             thread.IsBackground = true;
             thread.Start();
         }

2.接受数据

  /// <summary>
         /// 接受消息
         /// </summary>
         private void ReceiveData()
         {
             byte[] data = new byte[];
             IPEndPoint endPoint = new IPEndPoint(IPAddress.Any, );
             EndPoint remote = (EndPoint)endPoint;
             while (true)
             {
                 int len = ;
                 try
                 {
                    len = ServerSocket.ReceiveFrom(data, ref remote);
                    string str = Encoding.Default.GetString(data, , len);
                    string[] points = str.Split(',');
                    int x = int.Parse(points[]);
                    int y = int.Parse(points[]);
                    Point p = new Point(x, y);
                    Thread thread = new Thread(new ParameterizedThreadStart(drawPoint));
                    thread.IsBackground = true;
                    thread.Start(p);
                 }
                 catch (Exception  ex)
                 {

                 }
             }

         }

3.绘制

 /// <summary>
         /// 绘制
         /// </summary>
         /// <param name="p"></param>
         public void drawPoint(object p)
         {

             Point point = (Point)p;
             Graphics g = this.panel1.CreateGraphics();
             Pen pen = new Pen(Color.Black);
             g.DrawEllipse(pen, point.X, point.Y, , );
         }

源码下载: http://download.csdn.net/detail/gongchao1212/9591239