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using System;
using System.Collections.Generic;
using System.Text;
using System.Net.Sockets;
using System.Threading;
using System.Net;
using System.IO;

namespace myServer
{
    class Program
    {
        static void Main(string[] args)
        {
            Server srv = new Server();
        }
    }

    class Server
    {
        private TcpListener tcpListener;
        private Thread listenThread;

        public Server()
        {
            this.tcpListener = new TcpListener(IPAddress.Any, 3000);
            this.listenThread = new Thread(new ThreadStart(ListenForClients));
            this.listenThread.Start();
        }

        private void ListenForClients()
        {
            this.tcpListener.Start();

            while (true)
            {
                //blocks until a client has connected to the server
                TcpClient client = this.tcpListener.AcceptTcpClient();

                Console.WriteLine("Hello Server");

                //create a thread to handle communication
                //with connected client
                Thread clientThread = new Thread(new ParameterizedThreadStart(HandleClientComm));
                clientThread.Start(client);
            }
        }

        private void HandleClientComm(object client)
        {
            TcpClient tcpClient = (TcpClient)client;
            NetworkStream clientStream = tcpClient.GetStream();

            byte[] message = new byte[4096];
            int bytesRead;

            while (true)
            {
                bytesRead = 0;

                try
                {
                    //blocks until a client sends a message
                    bytesRead = clientStream.Read(message, 0, 4096);
                }
                catch(Exception ex)
                {
                    //a socket error has occured
                    Console.WriteLine(ex.Message);
                    break;
                }

                if (bytesRead == 0)
                {
                    //the client has disconnected from the server
                    break;
                }

                ASCIIEncoding encoder = new ASCIIEncoding();

                //Send Back ...
                Console.WriteLine(encoder.GetString(message, 0, bytesRead));
                clientStream.Write(message, 0, message.Length);


                /* ####### Erweiterung (s.u.) ######## */


            }
            tcpClient.Close();
        }
    }
}					

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                byte[] img = File.ReadAllBytes("c:\\1.jpg");
                
                message = encoder.GetBytes(img.Length+"\n");
                clientStream.Write(message, 0, message.Length);