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);

-------------------------------------------------------------------这里是分割线-----------------------------------------------

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[1024 * 1024];
            int j = 1000;
            Random r = new Random(100);
            while (j >0)
            {
                j--;
                int x = r.Next(500);
                int y = r.Next(500);
                string msg = x.ToString() +","+ y.ToString();
                data = Encoding.Default.GetBytes(msg);
                for (int k = 0; 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[1024];

            IPEndPoint ip = new IPEndPoint(IPAddress.Parse("192.168.10.179"), 50000);
            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[1024];
            IPEndPoint endPoint = new IPEndPoint(IPAddress.Any, 0);
            EndPoint remote = (EndPoint)endPoint;
            while (true)
            {
                int len = 0;
                try
                {
                   len = ServerSocket.ReceiveFrom(data, ref remote);
                   string str = Encoding.Default.GetString(data, 0, len);
                   string[] points = str.Split(',');
                   int x = int.Parse(points[0]);
                   int y = int.Parse(points[1]);
                   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, 5, 5);
        }

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