C# socket program

Question

Hello I am doing a socket program in C# and now I have got a problem. I use this server program code and this client code that I have been finding. I have ben modifying it some. So the problem I haw is that I do want to be able to disconnect from the server, I have been trying and googling it a lot but can't find out how to do it. What is the easy way to do it with this code??

the client code

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Net.Sockets;

namespace soket_client_delen
{

public partial class Form1 : Form
{
    System.Net.Sockets.TcpClient clientSocket = new System.Net.Sockets.TcpClient();

    public Form1()
    {
        InitializeComponent();
        this.textBox2.KeyPress += new System.Windows.Forms.KeyPressEventHandler(CheckKeys);
    }
    private void CheckKeys(object sender, System.Windows.Forms.KeyPressEventArgs e)
    {
        if (e.KeyChar == (char)13)
        {
            // Then Enter key was pressed
            if (checkBox1.Checked ==true)
                send();
        }
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        msg("Client Started");
        clientSocket.Connect("127.0.0.1", 8888);

        label1.Text = "Client Socket Program - Server Connected ...";
    }


    private void button1_Click_1(object sender, EventArgs e)
    {
        send();
    }

    public void send()
    {
        NetworkStream serverStream = clientSocket.GetStream();
        byte[] outStream = System.Text.Encoding.ASCII.GetBytes(textBox2.Text +"$");
        textBox2.Text = "";
        serverStream.Write(outStream, 0, outStream.Length);
        serverStream.Flush();

        byte[] inStream = new byte[10025];
        serverStream.Read(inStream, 0, (int)clientSocket.ReceiveBufferSize);
        string returndata = System.Text.Encoding.ASCII.GetString(inStream);
        msg("Data from Server : " + returndata);
    }


    public void msg(string mesg)
    {
        textBox1.Text = textBox1.Text + Environment.NewLine + " >> " + mesg;
    }

    private void button2_Click(object sender, EventArgs e)
    {

    }

}
}

and server code:

using System;
using System.Net.Sockets;
using System.Text;
using System.Threading;

namespace soket_serverdelen
{
class Program
{
    static void Main(string[] args)
    {
        TcpListener serverSocket = new TcpListener(8888);
        TcpClient clientSocket = default(TcpClient);
        int counter = 0;

        serverSocket.Start();
        Console.WriteLine(" >> " + "Server Started");

        counter = 0;
        while (true)
        {
            counter += 1;
            clientSocket = serverSocket.AcceptTcpClient();
            Console.WriteLine(" >> " + "Client No:" + Convert.ToString(counter) + " started!");
            handleClinet client = new handleClinet();
            client.startClient(clientSocket, Convert.ToString(counter));
        }

        clientSocket.Close();
        serverSocket.Stop();
        Console.WriteLine(" >> " + "exit");
        Console.ReadLine();
    }
}

//Class to handle each client request separatly
public class handleClinet
{
    TcpClient clientSocket;
    string clNo;
    public void startClient(TcpClient inClientSocket, string clineNo)
    {
        this.clientSocket = inClientSocket;
        this.clNo = clineNo;
        Thread ctThread = new Thread(doChat);
        ctThread.Start();
    }
    private void doChat()
    {
        int requestCount = 0;
        byte[] bytesFrom = new byte[10025];
        string dataFromClient = null;
        Byte[] sendBytes = null;
        string serverResponse = null;
        string rCount = null;
        requestCount = 0;

        while ((true))
        {
            try
            {
                requestCount = requestCount + 1;
                NetworkStream networkStream = clientSocket.GetStream();
                networkStream.Read(bytesFrom, 0, (int)clientSocket.ReceiveBufferSize);
                dataFromClient = System.Text.Encoding.ASCII.GetString(bytesFrom);
                dataFromClient = dataFromClient.Substring(0, dataFromClient.IndexOf("$"));

                    rCount = Convert.ToString(requestCount);
                    serverResponse = "Server to clinet(" + clNo + ") " + rCount;
                    sendBytes = Encoding.ASCII.GetBytes(serverResponse);
                    networkStream.Write(sendBytes, 0, sendBytes.Length);
                    networkStream.Flush();
                    Console.WriteLine(" >> " + serverResponse);
            }
            catch (Exception ex)
            {
                Console.WriteLine(" >> " + ex.ToString());
            }
        }
    }
}
}

Thanks you for all help

Answer 1

You need to have both sides calling close. Typically, though not a hard and fast rule, the client terminates the connection and the server side responds to that. So, when your client is done transmitting/receiving, the client side calls close. The server side then responds to that and calls close on its side.

For client side:

NetworkStream ns = clientSocket.GetStream();
// send important stuff
// receive important stuff from server
ns.Close();

For the server side:

NetworkStream ns = clientSocket.GetStream();
int bytesRead;
while((bytesRead = ns.Read(buffer, 0, buffer.Length)) >= 0) {
    if(bytesRead > 0) {
        // do really important stuff
    } else if(bytesRead == 0) {
        // client has trasmitted FIN packet, close and exit thread
        ns.Close();
    } else {
        // handle error condition
        // probably close the connection
    }
}

The above code is a model only. I've not tested it. You're using network streams so this example (I think) should be helpful. I usually use select() (from the windows API, .NET exposes it in the Socket class) for doing this. Basically, when either side closes the connection, via Close(), the Windows TCP stacks send a TCP FIN packet. This signals that the originating side wishes to close the connection. Also, someone commented that you should wrap your use of these streams in a using clause. That's imperative if you're not going to call Close() directly.

Answer 2

Typically the client would send a logoff-signal to the server. Upon receiving this message the server closes the connection. The client should run a loop untill serverStream.Socket.Closed = True before exiting.

Answer 3

Did you try clientSocket.Close()? http://msdn.microsoft.com/en-us/library/system.net.sockets.tcpclient.close.aspx