system.net.sockets.tcplistener

using System;

using System.IO;

using System.Net;

using System.Net.Sockets;

using System.Text;

class MyTcpListener

{

public static void Main()

{

TcpListener server=null;

try

{

// Set the TcpListener on port 13000.

Int32 port = 13000;

IPAddress localAddr = IPAddress.Parse("127.0.0.1");

// TcpListener server = new TcpListener(port);

server = new TcpListener(localAddr, port);

// Start listening for client requests.

server.Start();

// Buffer for reading data

Byte[] bytes = new Byte[256];

String data = null;

// Enter the listening loop.

while(true)

{

Console.Write("Waiting for a connection... ");

// Perform a blocking call to accept requests.

// You could also user server.AcceptSocket() here.

TcpClient client = server.AcceptTcpClient();

Console.WriteLine("Connected!");

data = null;

// Get a stream object for reading and writing

NetworkStream stream = client.GetStream();

int i;

// Loop to receive all the data sent by the client.

while((i = stream.Read(bytes, 0, bytes.Length))!=0)

{

// Translate data bytes to a ASCII string.

data = System.Text.Encoding.ASCII.GetString(bytes, 0, i);

Console.WriteLine("Received: {0}", data);

// Process the data sent by the client.

data = data.ToUpper();

byte[] msg = System.Text.Encoding.ASCII.GetBytes(data);

// Send back a response.

stream.Write(msg, 0, msg.Length);

Console.WriteLine("Sent: {0}", data);

}

// Shutdown and end connection

client.Close();

}

}

catch(SocketException e)

{

Console.WriteLine("SocketException: {0}", e);

}

finally

{

// Stop listening for new clients.

server.Stop();

}

Console.WriteLine("\nHit enter to continue...");

Console.Read();

}

}