No connection between client and server.

[haanjae]

hello, im working on c# client server program, no error, but i don't know why both client and server cannot connect, no response at all. i think something is wrong in my codes and i seriously don't understand whats the problem. Please help me. Thanks in advance.

server 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; //networking
using System.Net.Sockets; //networking
using System.Threading; //networking
using System.Net.NetworkInformation; 

namespace NBCS_serverlogin
{
    public partial class NBCSadmin : Form
    {
        private TcpListener tcpListener;
        private Thread threadTcp;
        static NetworkStream clientStream;
        const int portnumber = 3333;

        public NBCSadmin()
        {
            InitializeComponent();
            portnotxt.Text = "3333";
            // initiateListen();
        }

        private void initiateListen()
        {
            //Tcp
            this.tcpListener = new TcpListener(IPAddress.Any, portnumber);
            tcpListener.Start();
            int intPort = Convert.ToInt32(portnotxt.Text.Trim());
            this.threadTcp = new Thread(new ThreadStart(ListenToClients));
            
        }

        //listen for connected client 
        private void ListenToClients()
        {
            //tcpListener.Start(); 

            while (true)
            {
                try
                {
                    // block till client connect to server
                    TcpClient clientCom = this.tcpListener.AcceptTcpClient(); 

                    //handle connected clients
                    Thread threadClient = new Thread(new ParameterizedThreadStart(HandleClients));
                    threadClient.Start(clientCom);
                    constatuslabel.Text = "Received Client Connection.";

                }
                catch (SocketException)
                {
                    MessageBox.Show ("error");
                }
            }
        }
        private void HandleClients(object clientCom)
        {
            TcpClient tcpClient = (TcpClient)clientCom;
            clientStream = tcpClient.GetStream();

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

            while (true)
            {
                bytesRead = 0;

                try
                {
                    bytesRead = clientStream.Read(message, 0, 4096);
                }

                catch (Exception)
                {
                    // error happened
                    break;
                }

                if (bytesRead == 0)
                {
                    // client diconnected to server
                    constatuslabel.Text = "Client has disconnected from the server.";
                    break;
                }

                //msg has been successfully received
                ASCIIEncoding asciiEncoder = new ASCIIEncoding();
                // output msg
                constatuslabel.Text = tcpClient.Client.LocalEndPoint + "" + tcpClient.Client.RemoteEndPoint + asciiEncoder.GetString(message, 0, bytesRead);

                //System.Diagnostics.Debug.WriteLine(asciiEncoder.GetString(message, 0, bytesRead));
            }
            // (button)
            tcpClient.Close();
        }

        private void connecttoclientbtn_Click_1(object sender, EventArgs e)
        {
            initiateListen();
            constatuslabel.Text = "Waiting for a connection...";
            
        }

        private void stopconnbtn_Click(object sender, EventArgs e)
        {
            tcpListener.Stop();
            constatuslabel.Text = "Connection disconnected...";
        }

    }
}

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;
using System.Net.Sockets;
using System.Threading;
using System.IO;

namespace NBCS_Client
{
    public partial class NBCSuser : Form
    {
        static TcpClient clientuser;
        IPEndPoint serverEndPoint;
        NetworkStream clientStream;
        const int portnumber = 3333;
        string myIPAdd = string.Empty; 
        string strgAddress = string.Empty;

        public NBCSuser()
        {

            InitializeComponent();
            ipaddtxt.Text = "127.0.0.1";
            portnotxt.Text = "3333";
        }

        public void initiateListenUser()
        {
            clientuser = new TcpClient();

            //get the remote ip add
            IPAddress ipaddress = IPAddress.Parse(ipaddtxt.Text.Trim());
            int intPort = System.Convert.ToInt32(portnotxt.Text.Trim());
            //create end point
            serverEndPoint = new IPEndPoint(ipaddress, portnumber);

        }

        public void connectTcpServer()
        {
            clientuser.Connect(serverEndPoint);
            clientStream = clientuser.GetStream();

            //create thread to handle communication with connected client
            Thread threadClient = new Thread(new ParameterizedThreadStart(HandleClients));
            threadClient.Start(clientuser);

        }

        public void HandleClients(object clientuser)
        {
            TcpClient tcpclient = (TcpClient)clientuser;
            NetworkStream clientStream = tcpclient.GetStream();

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

            while (true)
            {
                bytesRead = 0;

                try
                {
                    //block until client send a msg
                    bytesRead = clientStream.Read(message, 0, 4096);
                }
                catch (SocketException)
                {
                    //socket error
                    break;
                }

                if (bytesRead == 0)
                {
                    //client disconnected to server
                    break;
                }
                //msg received successfully
                ASCIIEncoding asciiEncoder = new ASCIIEncoding();
                // output msg
                userconstatuslabel.Text = tcpclient.Client.LocalEndPoint + "" + tcpclient.Client.RemoteEndPoint + asciiEncoder.GetString(message, 0, bytesRead);
                //textFrmServer 

            }
            tcpclient.Close();

        }

        private void connectserverbtn_Click(object sender, EventArgs e)
        {
            initiateListenUser();
            connectTcpServer();
            userconstatuslabel.Text = "Connecting to server...";
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void exitbtn_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }
    }
}

[foamy]

Several things strike me as odd in regard to the server code...

- The port number never seems to be assigned to the listener. (EDIT: my bad, it is indeed assigned)
- The thread is never started.

[haanjae]

the thread is never started? i dont understand...

[foamy]

In the server code, I can't see any calls to start the 'threadTcp' thread. If that's the case, how do you expect it to do anything?