WPF UDP 客戶端exmplae

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
 
namespace UDP_Client.UDP
{
    class UDP_Client
    {
 
 
        private const int listenPort = 6800;
        private const String IP = "255.255.255.255";
        private UdpClient listener= new UdpClient(listenPort);
        private bool action_flag;
        public UDP_Get_message_action action = null;
 
        public  void StartListener()
        {
 
            Thread thread = new Thread(listener_action);
            thread.Start();
 
        }
 
        //讀取的資料
 
        private void listener_action()
        {
            IPAddress iPAddress = IPAddress.Parse(IP);
            IPEndPoint groupEP = new IPEndPoint(iPAddress, listenPort);
            byte[] bytes;
            String temp;
            action_flag = true;
 
            try
            {
                while (true)
                {
                     bytes = listener.Receive(ref groupEP);
                     temp=Encoding.ASCII.GetString(bytes, 0, bytes.Length);
                    if (action != null)
                    {
                        action.onGetMessage(temp);
                    }
 
                }
            }
            catch (SocketException e)
            {
                Console.WriteLine(e);
 
            }
            finally
            {
                listener.Close();
            }
 
 
        }
 
        public  void close()
        {
            if (action_flag == true)
            {
                action_flag = false;
                try
                {
                    listener.Close();
                }
                catch (SocketException e)
                {
 
                }
            }
 
 
        }
 
 
    }
}