[RESOLVED] Need help with UDP server code

I'm having a few problems with this code
1. first, when I click start server and stop it, it gives no exception even though the ports in use (I have it in use to make it throw an error when binding )

2. When I click Start server the 2nd time, I get the following error:

Code:

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An unhandled exception of type 'System.StackOverflowException' occurred in System.Windows.Forms.dll

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Here is my code:

Code:

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    public partial class Form1 : Form
    {
        private int server_port;
        public Thread serverThread;
        bool isRunning;
   


        /*
        * add_log()
        * handle logging
        */
        delegate void add_log_d(string text);
        private  void add_log(string text)
        {
            if (this.txtLog.InvokeRequired)
            {
                this.txtLog.Invoke(new add_log_d(this.add_log), new object[] { text });
            }
            else
            {
                this.add_log(text);
            }
        }


        /*
        * StartRecvFrom()
        * - Start listening for data and handle it.
        */
        public void StartRecvFrom()
        {
            IPHostEntry localhost;
            try
            {
                // bind to localhost
                Socket sckUdp = new Socket( AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp );
                try
                {
                    localhost = Dns.GetHostByName( Dns.GetHostName() );
                }
                catch( Exception e )
                {
                    add_log(">> Error - " + e.ToString() + "\n");
                    return;
                }
                IPEndPoint localIP = new IPEndPoint(localhost.AddressList[0], server_port );
                sckUdp.Bind( localIP );


                // begin listening for data
                while( true )
                {
                    byte[] received = new byte[32768];
                    IPEndPoint tmpIP = new IPEndPoint( localhost.AddressList[0], server_port );
                    EndPoint remoteIP  = (tmpIP);
                    int bytes_received = sckUdp.ReceiveFrom( received, ref remoteIP );
                    string data = System.Text.Encoding.ASCII.GetString( received );

                    add_log(">> Received packet from " + remoteIP.ToString() + ":\n" + data + "\n\n");
                }
            }
            catch( SocketException se )
            {
                add_log(">> Socket Exception occurred - " + se.ToString() + "\n");
            }
        }


        /*
        * StartUDPServer
        * - Start the server thread.
        */
        public void StartUDPServer()
        {
            try
            {
                serverThread = new Thread(new ThreadStart(StartRecvFrom));
                serverThread.IsBackground = true;
                serverThread.Start();
                isRunning = true;
            }
            catch (Exception e)
            {
                add_log(">> Error starting server - " + e.ToString() + "\n");
                serverThread.Abort();
                isRunning = false;
            }
        }

        /*
        * StopUDPServer()
        * - Stop the UDP server thread.
        */
        public void StopUDPServer()
        {
            try
            {
                serverThread.Abort();
                isRunning = false;
            }
            catch (Exception e)
            {
                add_log(">> Error stopping server - " + e.ToString() + "\n");
            }
        }



        private void btnStartStop_Click(object sender, EventArgs e)
        {
            if (btnStartStop.Text == "Start Server")
            {
                btnStartStop.Text = "Stop Server";
                StartUDPServer();
            }
            else if ( btnStartStop.Text == "Stop Server" )
            {
                btnStartStop.Text = "Start Server";
                StopUDPServer();
            }
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            btnStartStop.Text = "Start Server";
            isRunning = false;
            server_port = 21000;
        }

        public Form1()
        {
            InitializeComponent();
        }
    }

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What am I doing wrong? It's probably something stupid.

You could try this instead.

Code:

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private void add_log(string text)
{
  Invoke(new MethodInvoker(delegate { txtLog.Items.Add(text); }));
}

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However, you're going to still get another exception. You're already bound to a socket and trying to bind again, but that code should take care of the overflow.

Okay, got it working now thanks to that code. Also fixed the other exception.

Marking thread resolved. Thanks for the help.