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

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

第二种，使用UdpClient类

1  IPAddress address = IPAddress.Parse(txtLocalIp.Text);
2             int port = Int32.Parse(txtLocalPort.Text);
3             IPEndPoint endPoint = new IPEndPoint(address, port);
4             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。

 1   private void btnStart_Click(object sender, EventArgs e)
 2         {
 3             if (serverSocket != null)
 4             {
 5                 return;
 6             }
 7             IPEndPoint ip = new IPEndPoint(IPAddress.Parse(txtIP.Text), int.Parse(txtPort.Text));
 8             serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
 9             serverSocket.Bind(ip);
10
11             AppendTextToTxtLog(string.Format("服务器端是{0},正在等待客户端的连接",ip.ToString()));
12             Thread thread = new Thread(ReceiveData);
13             thread.IsBackground = true;
14             thread.Start();
15
16         }

3.发送数据

 1  private void SendData()
 2         {
 3             byte[] data = new byte[1024 * 1024];
 4             int j = 1000;
 5             Random r = new Random(100);
 6             while (j >0)
 7             {
 8                 j--;
 9                 int x = r.Next(500);
10                 int y = r.Next(500);
11                 string msg = x.ToString() +","+ y.ToString();
12                 data = Encoding.Default.GetBytes(msg);
13                 for (int k = 0; k < RemoteList.Count; k++)
14                 {
15                     int i = serverSocket.SendTo(data, data.Length, SocketFlags.None,RemoteList[k]);
16                     AppendTextToTxtLog(string.Format("发送给客户端{0}的消息是{1}", RemoteList[k].ToString(), msg));
17                 }
18             }
19         }

客户端

1.连接到服务器端

 1    private void btnConnected_Click(object sender, EventArgs e)
 2         {
 3             byte[] data = new byte[1024];
 4
 5             IPEndPoint ip = new IPEndPoint(IPAddress.Parse("192.168.10.179"), 50000);
 6             ServerSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
 7             string welcome = "你好!";
 8             data = Encoding.Default.GetBytes(welcome);
 9             ServerSocket.SendTo(data, data.Length, SocketFlags.None, ip);
10             Thread thread = new Thread(ReceiveData);
11             thread.IsBackground = true;
12             thread.Start();
13         }

2.接受数据

 1  /// <summary>
 2         /// 接受消息
 3         /// </summary>
 4         private void ReceiveData()
 5         {
 6             byte[] data = new byte[1024];
 7             IPEndPoint endPoint = new IPEndPoint(IPAddress.Any, 0);
 8             EndPoint remote = (EndPoint)endPoint;
 9             while (true)
10             {
11                 int len = 0;
12                 try
13                 {
14                    len = ServerSocket.ReceiveFrom(data, ref remote);
15                    string str = Encoding.Default.GetString(data, 0, len);
16                    string[] points = str.Split(‘,‘);
17                    int x = int.Parse(points[0]);
18                    int y = int.Parse(points[1]);
19                    Point p = new Point(x, y);
20                    Thread thread = new Thread(new ParameterizedThreadStart(drawPoint));
21                    thread.IsBackground = true;
22                    thread.Start(p);
23                 }
24                 catch (Exception  ex)
25                 {
26
27
28                 }
29             }
30
31         }

3.绘制

 1 /// <summary>
 2         /// 绘制
 3         /// </summary>
 4         /// <param name="p"></param>
 5         public void drawPoint(object p)
 6         {
 7
 8             Point point = (Point)p;
 9             Graphics g = this.panel1.CreateGraphics();
10             Pen pen = new Pen(Color.Black);
11             g.DrawEllipse(pen, point.X, point.Y, 5, 5);
12         }

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