c# socket program

How to use socket in client application?
//first, new a socket object.
//socket class is included in system.net.sockets.
//this socket can be used to tcp/ip application:
Socket s = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
//this socket can be used to udp application:
Socket s = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);

//second, connect to sever
public void Connect(EndPoint remoteEP)
//the endpoint is composed of IP and port.
//IP can be get through the Parse method of IPAddress class:
IPAddress myIP = IPAddress.Parse("192.168.1.2");
//you can also get ip from a domain name through the method below:
IPHostEntry ipHostInfo = Dns.Resolve("host.contoso.com");
IPAddress ipAddress = ipHostInfo.AddressList[0];
// knowing the ip and port, u can get the EndPoint:
IPEndPoint ipe = new IPEndPoint(ipAddress,11000);
// having the EndPoint, connect to server:
try {
s.Connect(ipe);
}
catch(ArgumentNullException ae) {
Console.WriteLine("ArgumentNullException : {0}", ae.ToString());
}
catch(SocketException se) {
Console.WriteLine("SocketException : {0}", se.ToString());
}
catch(Exception e) {
Console.WriteLine("Unexpected exception : {0}", e.ToString());
}

// if you want to send data to server, you can use "send" method.
public int Send(byte[], int, SocketFlags);
// before you send a string to server, you must convert it to bytes.
byte[] bytesSendStr=new byte[1024];
bytesSendStr=Encoding.ASCII.GetBytes(sendStr);
// then send bytes to server:
socket.Send(bytesSendStr,bytesSendStr.Length,0);

// you can use "recieve" method to recieve data from server.
public int Receive(byte[],int,SocketFlags);
// you probably need to convert bytes to string.
byte[] recvBytes=new byte[1024];
int bytes=0;
while(true)
{
bytes=socket.Receive(recvBytes,recvBytes.Length,0);
if(bytes<=0)
break;
recvStr+=Encoding.ASCII.GetString(recvBytes,0,bytes);
}

//when you needn't socket any more, shutdown and close it.
public void Shutdown( SocketShutdown how );
public void Close();

How to use socket in server application?
// same to client app, u need new a socket also.
Scoket listener(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
// u can get local IP as below:
IPHostEntry ipHostInfo = Dns.Resolve(Dns.GetHostName());
IPAddress ipAddr = ipHostInfo.AddressList(0); 
// then, bind the socket with a local endpoint.
public void Bind( EndPoint localEP ); 
// listen to connect request.
public void Listen( int backlog );
for example: listener.Listen(10)
// if hear a connect request, accept it and new a socket more to treat later request.
for example: Scoket handler = listener.Accept();
// when this session is over, shutdown and close handler.
handler.Shutdown(SocketShutdown.Both);
handler.Close();
// when server app exit, shutdown and close listener.

Those codes are not runable, which only expressed how to use socket.