Socket-based UDP packet sending program

UDP (user Datagram Protocol, Subscriber Datagram Protocol) is a commonly used transport layer protocol in the Internet, which provides the simplest protocol mechanism for sending messages to another user program. As with TCP, its default downlevel protocol is IP.UDP-oriented, does not provide commit and copy protection, and therefore does not guarantee the reliable transmission of data. UDP is generally used in high-reliability LANs.

. NET can use the socket class to write UDP-based network programs, Whenever you create a socket, select the third argument of the constructor function as the enumeration value PROTOCOLTYPE.UDP. In addition, the. Net System.Net.Sockets namespace also has a UdpClient class that can be specifically used for UDP network programming. -----Excerpt from < C#.NET framework Advanced Programming Technology Case Tutorial Guo Wenji et p163>

First, using the socket class

1  New int . Parse (Txtport.text)); 2             Socket  New  socket (addressfamily.internetwork, Sockettype.dgram, protocoltype.udp); 3             Serversocket.bind (IP);

Second, use the UdpClient class

1  IPAddress address = Ipaddress.parse (txtlocalip.text); 2             int port = int32.parse (txtlocalport.text); 3             New IPEndPoint (address, port); 4             New UdpClient (EndPoint);

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This paper mainly uses the first one, based on the socket to write a UDP packet program. The server continues to contract, and the client draws points on the form based on the received point data, as shown in the following:

One. Server-side

1. Create a socket object that binds the server-side IP and port number.

2. Create a thread for the user to obtain the IP and port number of the client. Basically, the client connects to the server and sends a "hello" message, and the server side can get the IP and port of the client.

1   Private voidbtnStart_Click (Objectsender, EventArgs e)2         {3             if(ServerSocket! =NULL)4             {5                 return;6             }7IPEndPoint IP =NewIPEndPoint (Ipaddress.parse (Txtip.text),int. Parse (Txtport.text));8ServerSocket =Newsockets (AddressFamily.InterNetwork, Sockettype.dgram, protocoltype.udp);9 serversocket.bind (IP);Ten  OneAppendtexttotxtlog (string. Format ("Server side is {0}, waiting for client connection", IP. ToString ())); AThread thread =NewThread (receivedata); -Thread. IsBackground =true; - thread. Start (); the  -}

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3. Send data

1  Private voidSendData ()2         {3             byte[] data =New byte[1024x768*1024x768];4             intj = +;5Random r =NewRandom ( -);6              while(J >0)7             {8j--;9                 intx = R.next ( -);Ten                 inty = R.next ( -); One                 stringmsg = x.tostring () +","+y.tostring (); Adata =Encoding.Default.GetBytes (msg); -                  for(intK =0; K < Remotelist.count; k++) -                 { the                     inti =serversocket.sendto (data, data. Length, Socketflags.none,remotelist[k]); -Appendtexttotxtlog (string. Format ("the message sent to client {0} is {1}", Remotelist[k]. ToString (), msg)); -                 } -             } +}

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Client

1. Connect to the server side

1    Private voidBtnconnected_click (Objectsender, EventArgs e)2         {3             byte[] data =New byte[1024x768];4 5IPEndPoint IP =NewIPEndPoint (Ipaddress.parse ("192.168.10.179"),50000);6ServerSocket =Newsockets (AddressFamily.InterNetwork, Sockettype.dgram, protocoltype.udp);7             stringWelcome ="Hi there!";8data =Encoding.Default.GetBytes (welcome);9 serversocket.sendto (data, data. Length, Socketflags.none, IP);TenThread thread =NewThread (receivedata); OneThread. IsBackground =true; A thread. Start (); -}

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2. Acceptance of data

1  /// <summary>2         ///Accept Message3         /// </summary>4         Private voidReceivedata ()5         {6             byte[] data =New byte[1024x768];7IPEndPoint EndPoint =NewIPEndPoint (Ipaddress.any,0);8EndPoint remote =(EndPoint) EndPoint;9              while(true)Ten             { One                 intLen =0; A                 Try -                 { -Len = serversocket.receivefrom (data,refremote); the                    stringstr = Encoding.Default.GetString (data,0, Len); -                    string[] points = str. Split (','); -                    intx =int. Parse (points[0]); -                    inty =int. Parse (points[1]); +Point P =NewPoint (x, y); -Thread thread =NewThread (NewParameterizedthreadstart (Drawpoint)); +Thread. IsBackground =true; A thread. Start (p); at                 } -                 Catch(Exception ex) -                 { -                      -                     -                 } in             } -          to}

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3. Draw

1 /// <summary>2         ///Drawing3         /// </summary>4         /// <param name= "p" ></param>5          Public voidDrawpoint (Objectp)6         {7 8Point point =(point) p;9Graphics g = This. Panel1. CreateGraphics ();TenPen pen =NewPen (color.black); OneG.drawellipse (pen, point. X, point. Y5,5); A}

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SOURCE Download: http://download.csdn.net/detail/gongchao1212/9591239

Socket-based UDP packet sending program