C# socket programming

TCP Client


using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.Net.Sockets;
using System.Text;


namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            Connect("localhost", "hello");
        }
        static void Connect(String server, String message)
        {
            try
            {
                // Create a TcpClient.
                // Note, for this client to work you need to have a TcpServer 
                // connected to the same address as specified by the server, port
                // combination.
                Int32 port = 13000;
                TcpClient client = new TcpClient(server, port);


                // Translate the passed message into ASCII and store it as a Byte array.
                Byte[] data = System.Text.Encoding.ASCII.GetBytes(message);


                // Get a client stream for reading and writing.
                //  Stream stream = client.GetStream();


                NetworkStream stream = client.GetStream();


                // Send the message to the connected TcpServer. 
                stream.Write(data, 0, data.Length);


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


                // Receive the TcpServer.response.
                // Buffer to store the response bytes.
                data = new Byte[256];


                // String to store the response ASCII representation.
                String responseData = String.Empty;


                // Read the first batch of the TcpServer response bytes.
                Int32 bytes = stream.Read(data, 0, data.Length);
                responseData = System.Text.Encoding.ASCII.GetString(data, 0, bytes);
                Console.WriteLine("Received: {0}", responseData);


                // Close everything.
                client.Close();
            }
            catch (ArgumentNullException e)
            {
                Console.WriteLine("ArgumentNullException: {0}", e);
            }
            catch (SocketException e)
            {
                Console.WriteLine("SocketException: {0}", e);
            }


            Console.WriteLine("\n Press Enter to continue...");
            Console.Read();
        }
    }
}


TCP Listener



using System;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Text;


class MyTcpListener
{
    public static void Main()
    {
        try
        {
            // Set the TcpListener on port 13000.
            Int32 port = 13000;
            IPAddress localAddr = IPAddress.Parse("127.0.0.1");


            // TcpListener server = new TcpListener(port);
            TcpListener 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(String.Format("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(String.Format("Sent: {0}", data));
                }


                // Shutdown and end connection
                client.Close();
            }
        }
        catch (SocketException e)
        {
            Console.WriteLine("SocketException: {0}", e);
        }


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