求域名查询源码(asp.net(c#))急

///   <summary>   

  ///   GET方式发送请求   

  ///   </summary>   

  ///   <param   name="requestUrl">请求地址</param>   

  ///   <returns>响应字符串</returns>   

  public   string   SendRequest(   string   requestUrl   )   

  {   

  HttpWebRequest   httpWebRequest   =   (   HttpWebRequest   )   WebRequest.Create(   requestUrl   );   

  httpWebRequest.Method   =   "GET";   

  WebResponse   webResponse   =   httpWebRequest.GetResponse();   

  StreamReader   responseStream   =   new   StreamReader(   webResponse.GetResponseStream(),   System.Text.Encoding.UTF8   );   

  _responseStr   =   responseStream.ReadToEnd();   

  webResponse.Close();     

  responseStream.Close();   

  return   _responseStr;   

  }

public   string   Lookup(string   strDomain)   

  {   

  try   

  {   

  string   result="";   

  string   server="whois.internic.net";   

  string   ext=".com";   

  int   port=43;   

  int   address=-1;   

  string   domain=strDomain.Trim().ToLower();   

    

  if(domain.StartsWith("www."))   

  {   

  domain=domain.Substring(4,domain.Length-4);   

  }   

    

  if(domain==""   ||   domain.IndexOf(",")!=-1||   domain.IndexOf(";")!=-1||   domain.IndexOf("_")!=-1||   domain.IndexOf(".")==-1)   

  {   

  result="Please   enter   a   valid   domain   name.";   

  }   

  else   

  {   

  address=domain.IndexOf(".");   

  ext=domain.Substring(address);   

    

  switch   (ext)   

  {   

  case   ".com":   

  case   ".net":   

  case   ".org":   

  default:   

  server="whois.crsnic.net";   

  //server="whois.internic.net";   

  break;   

  case   ".biz":   

  case   ".info":   

  case   ".mil":   

  server="whois.networksolutions.com";   

  break;   

  case   ".edu":   

  server="whois.educause.net";   

  break;   

  case   ".cn":   

  case   ".com.cn":   

  case   ".net.cn":   

  case   ".org.cn":   

  //case   ".gov.cn":   

    

  case   ".bj.cn":   

  case   ".sh.cn":   

  case   ".tj.cn":   

  case   ".cq.cn":   

  case   ".he.cn":   

  case   ".nm.cn":   

  case   ".ln.cn":   

  case   ".jl.cn":   

  case   ".hl.cn":   

  case   ".js.cn":   

  case   ".zj.cn":   

  case   ".ah.cn":   

  case   ".hb.cn":   

  case   ".hn.cn":   

  case   ".gd.cn":   

  case   ".gx.cn":   

  case   ".hi.cn":   

  case   ".sc.cn":   

  case   ".gz.cn":   

  case   ".yn.cn":   

  case   ".xz.cn":   

  case   ".sn.cn":   

  case   ".gs.cn":   

  case   ".qh.cn":   

  case   ".nx.cn":   

  case   ".xj.cn":   

  case   ".tw.cn":   

  case   ".hk.cn":   

  case   ".mo.cn":   

  server="whois.cnnic.net.cn";   

  break;   

  }   

    

  //starting   lookup   

  UTF8Encoding   utf8   =   new   UTF8Encoding();   

  //   Connect   to   the   whois   server   

  TcpClient   tcpClient   =   new   TcpClient();   

  tcpClient.Connect(server,port);   

  NetworkStream   networkStream     =   tcpClient.GetStream();   

  //   Send   the   domain   name   to   the   whois   server   

    

  domain=domain.Replace("0x00","");   

  byte[]   buffer=Encoding.GetEncoding("GB2312").GetBytes(domain   +   "\r\n");   

  //byte[]   buffer   =   utf8.GetBytes(domain   +   "\r\n");   

  networkStream.Write(buffer,0,buffer.Length);   

  //   Read   back   the   results   

  buffer   =   new   byte[10240];   

    

  int   i   =   networkStream.Read(buffer,0,buffer.Length);   

  while   (   i   >   0)   

  {   

  i   =   networkStream.Read(buffer,0,buffer.Length);   

  result   +=   utf8.GetString(buffer);   

  //result   +=Encoding.GetEncoding("GB2312").GetString(buffer);   

  }   

  networkStream.Close();   

  tcpClient.Close();   

  }   

  //return   the   lookup   resutlt   

  result=result.Replace("\u0000","");   

  return   result;         

  }   

    

  catch(Exception   e)   

  {   

  return   e.Message;   

  //return   "Sorry.Lookup   is   false.Please   check   the   format   of   domain   or   internet   connection.";   

  }   

    

    

  }