关于Socket的学习代码

using System;
 using System.Text;
 using System.IO;
 using ;
 using .Sockets;public class Sample
 { 
   public static string DoSocketGet(string server) 
   { 
 
     //Set up variables and String to write to the server.
     Encoding ASCII = Encoding.ASCII;
     string Get = "GET / HTTP/1.1\r\nHost: " + server + 
                  "\r\nConnection: Close\r\n\r\n";
     Byte[] ByteGet = ASCII.GetBytes(Get);
     Byte[] RecvBytes = new Byte[256];
     String strRetPage = null;     // IPAddress and IPEndPoint represent the endpoint that will
     //   receive the request.
     // Get first IPAddress in list return by DNS.     try
     { 
        // Define those variables to be evaluated in the next for loop and 
       // then used to connect to the server. These variables are defined
       // outside the for loop to make them accessible there after.
       Socket s = null;
       IPEndPoint hostEndPoint;
       IPAddress hostAddress = null;
       int conPort = 80;      // Get DNS host information.
       IPHostEntry hostInfo = Dns.Resolve(server);
       // Get the DNS IP addresses associated with the host.
       IPAddress[] IPaddresses = hostInfo.AddressList;      // Evaluate the socket and receiving host IPAddress and IPEndPoint. 
       for (int index=0; index<IPaddresses.Length; index++)
       { 
 
         hostAddress = IPaddresses[index];
         hostEndPoint = new IPEndPoint(hostAddress, conPort);         // Creates the Socket to send data over a TCP connection.
         s = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp );  
         // Connect to the host using its IPEndPoint.
         s.Connect(hostEndPoint);        if (!s.Connected)
         { 
 
           // Connection failed, try next IPaddress.
           strRetPage = "Unable to connect to host";
           s = null;
           continue;
         }        // Sent the GET request to the host.
         s.Send(ByteGet, ByteGet.Length, 0);       } // End of the for loop.      
  
       // Receive the host home page content and loop until all the data is received.
       Int32 bytes = s.Receive(RecvBytes, RecvBytes.Length, 0);
       strRetPage = "Default HTML page on " + server + ":\r\n";
       strRetPage = strRetPage + ASCII.GetString(RecvBytes, 0, bytes);
  
       while (bytes > 0)
       { 
 
         bytes = s.Receive(RecvBytes, RecvBytes.Length, 0);
         strRetPage = strRetPage + ASCII.GetString(RecvBytes, 0, bytes);
       }    
     } // End of the try block.
     
     catch(SocketException e) 
     { 
 
       Console.WriteLine("SocketException caught!!!");
       Console.WriteLine("Source : " + e.Source);
       Console.WriteLine("Message : " + e.Message);
     }
     catch(ArgumentNullException e)
     { 
 
       Console.WriteLine("ArgumentNullException caught!!!");
       Console.WriteLine("Source : " + e.Source);
       Console.WriteLine("Message : " + e.Message);
     }
     catch(NullReferenceException e)
     { 
 
       Console.WriteLine("NullReferenceException caught!!!");
       Console.WriteLine("Source : " + e.Source);
       Console.WriteLine("Message : " + e.Message);
     }
     catch(Exception e)
     { 
 
       Console.WriteLine("Exception caught!!!");
       Console.WriteLine("Source : " + e.Source);
       Console.WriteLine("Message : " + e.Message);
     }
     
     return strRetPage;}
    public static void Main()
    { 
 
       Console.WriteLine("请需入请求地址:");
       String server =Console.ReadLine();
       Console.WriteLine(DoSocketGet(server));
       
       //存一下档
       string path = @"D:\Socket.html";
       if(File.Exists(path))
       { 
 
  File.Delete(path);
       }
  using(FileStream fs =File.Create(path))
  { 
 
   Byte[] bs =new UTF8Encoding(true).GetBytes(DoSocketGet(server));
   fs.Write(bs,0,bs.Length);
  }
    }
  }