System.Net.WebClient client=new WebClient(); 
byte[] page=client.DownloadData("http://www.google.com"); 
string content=System.Text.Encoding.UTF8.GetString(page); 

string hostName="www.nnn.net"; 
label1.Text="xxx"; 
int port=80; 
IPHostEntry ipInfo=Dns.GetHostByName(hostName); 
//取得IPAddress[] 
IPAddress[] ipAddr=ipInfo.AddressList; 
//得到ip 
IPAddress ip=ipAddr[0]; 
IPEndPoint hostEP=new IPEndPoint(ip,port); 
Socket socket=new Socket(AddressFamily.InterNetwork,
SocketType.Stream,ProtocolType.Tcp); 

socket.Connect(hostEP); 

string sendStr="GET "+"/tryst/default.asp"+" HTTP/1.1\r\nHost: " + 
hostName + "\r\nConnection: Close\r\n\r\n"; 
//创建bytes字节数组以转换发送串 
byte[] bytesSendStr=new byte[1024]; 
//将发送内容字符串转换成字节byte数组 
bytesSendStr=Encoding.ASCII.GetBytes(sendStr); 
socket.Send(bytesSendStr,bytesSendStr.Length,0); 
//声明接收返回内容的字符串 
string recvStr=""; 
//声明字节数组，一次接收数据的长度为1024字节 
byte[] recvBytes=new byte[1024]; 
//返回实际接收内容的字节数 
int bytes=0; 
//循环读取，直到接收完所有数据 
while(true) 
{ 
bytes=socket.Receive(recvBytes,recvBytes.Length,0); 
//读取完成后退出循环 
if(bytes<=0) 
break; 
//将读取的字节数转换为字符串 
recvStr+=Encoding.ASCII.GetString(recvBytes,0,bytes); 
}