Shrutz Mhatz

Shrutz Mhatz

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UDP packet Sent once but received thrice

Apr 9 2012 8:07 AM
Hi,
I am writing a simple code to send and receive data on a udp socket.
the code works ok except for the data is getting received thrice .
I am new to this so please bare with me... :)

<<<<<<<<<<<<<<<<<<<sender code>>>>>>>>>>>>>>>>>>>

            Socket server = new Socket(AddressFamily.InterNetwork,SocketType.Dgram, 

ProtocolType.Udp);
            server.EnableBroadcast = false;
            server.ExclusiveAddressUse = false;

            IPEndPoint iep = new IPEndPoint(IPAddress.Parse("224.100.0.1"), 9050);
            
            byte[] data = Encoding.ASCII.GetBytes(textBox1.Text.Trim());
            server.SendTo(data, iep);
            
            server.Close();


<<<<<<<<<<<<<<<<<Receiver code>>>>>>>>>>>>>>>

 private void OnReceive(IAsyncResult ar)
        {

            try
            {
                UdpClient u = (UdpClient)((UdpState)(ar.AsyncState)).u;
                IPEndPoint e = (IPEndPoint)((UdpState)(ar.AsyncState)).e;

                UdpState s = new UdpState();
                s.e = e;
                s.u = u;

                Byte[] receiveBytes = u.EndReceive(ar,ref e);
                string receiveString = Encoding.ASCII.GetString(receiveBytes);
                s.e = e;
                listBox1.Items.Add("Received:" + receiveString+e.Address.ToString());

                u.BeginReceive(new AsyncCallback(OnReceive), s);
                
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }



        private void Form1_Load(object sender, EventArgs e)
        {
            CheckForIllegalCrossThreadCalls = false;//Will remove later
        }

        private void StartReceive_Click(object sender, EventArgs eA)
        {

            IPEndPoint iep = new IPEndPoint(IPAddress.Parse("224.100.0.1"), 9050);
            IPEndPoint e = new IPEndPoint(IPAddress.Any, 9050);
            UdpClient u = new UdpClient(e);

            u.Client.Blocking = false;
            UdpState s = new UdpState();
            s.e = e;
            s.u = u;
            s.u.Client.DontFragment = true;
            s.u.Client.Ttl = 1;
            listBox1.Items.Add("listening for messages");
            u.JoinMulticastGroup( IPAddress.Parse("224.100.0.1"));
            u.BeginReceive(new AsyncCallback(OnReceive), s);
        }



    public class UdpState
    {
        public IPEndPoint e;
        public UdpClient u;
    }

Answers (1)