Socket programming

Question

Hi.

I am trying to some socket programs. Below, server side program's codes. Its getting the messages from client with no problem. I want to count this messages length and sending again to client. But it doesnt work. Where am I mistaken?


        public NetworkStream str;
        public StreamReader str_rdr;
        public StreamWriter str_wrt;
        public Socket clientsoket;

public void Form1_Load(object sender, EventArgs e)
        {
            CheckForIllegalCrossThreadCalls = false;
            Thread thread_listener = new Thread(new ThreadStart(listen));
            thread_listener.Start();
        }

        public void listen()
        {
            TcpListener listener = new TcpListener(30000);
            
            while (true)
            {
                listener.Start();
                Socket clientsocket = listener.AcceptSocket();
            

                    NetworkStream str = new NetworkStream(clientsoket);
                
                    StreamReader str_rdr = new StreamReader(str);
                    string var1 = str_rdr.ReadLine();
                    textBox1.Text = var1; // ----> In here, I am seeing client's message.

                    StreamWriter str_wrt = new StreamWriter(str);
                    str_wrt.WriteLine(textBox1.Text.Length);
                    str_wrt.Flush();
            }
        }