UdpListener Class

The following example demonstrates how to create and use a UdpListener to receive UDP datagrams.

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

public class UdpReceiver
{
    private UdpClient udpClient;
    private bool isListening = false;

    public void StartListening(int port)
    {
        try
        {
            udpClient = new UdpClient(port);
            isListening = true;
            Console.WriteLine($"Listening on port {port}...");

            // Start a new thread to handle receiving data
            Thread receiveThread = new Thread(new ThreadStart(ReceiveData));
            receiveThread.Start();
        }
        catch (Exception e)
        {
            Console.WriteLine($"Error starting listener: {e.Message}");
        }
    }

    private void ReceiveData()
    {
        while (isListening)
        {
            try
            {
                IPEndPoint remoteEP = new IPEndPoint(IPAddress.Any, 0);
                byte[] receivedBytes = udpClient.Receive(ref remoteEP);
                string receivedMessage = Encoding.ASCII.GetString(receivedBytes);

                Console.WriteLine($"Received from {remoteEP}: {receivedMessage}");
            }
            catch (SocketException sockEx)
            {
                if (isListening) // Only log if we're supposed to be listening
                {
                    Console.WriteLine($"Socket Exception: {sockEx.Message}");
                }
                break; // Exit loop on socket errors if not explicitly stopped
            }
            catch (Exception e)
            {
                Console.WriteLine($"Error receiving data: {e.Message}");
            }
        }
        Console.WriteLine("Receive thread stopped.");
    }

    public void StopListening()
    {
        isListening = false;
        udpClient?.Close();
        Console.WriteLine("Listener stopped.");
    }

    public static void Main(string[] args)
    {
        UdpReceiver receiver = new UdpReceiver();
        int listenPort = 11000; // Example port

        receiver.StartListening(listenPort);

        Console.WriteLine("Press Enter to stop listening...");
        Console.ReadLine();

        receiver.StopListening();
    }
}