Udp廣播的發送與接收(C#＋UdpClient) 上篇

簡介：

　　Udp廣播消息用在局域網的消息傳遞很方便。本文使用UdpClient類在WPF下實現Udp廣播收發

發送：

        void MainWindow_Loaded(object sender, RoutedEventArgs e)
        {
            Loaded -= MainWindow_Loaded;
            UdpClient client = new UdpClient(new IPEndPoint(IPAddress.Any, 0));
            IPEndPoint endpoint = new IPEndPoint(IPAddress.Parse("255.255.255.255"), 7788);//默認向全世界所有主機發送即可，路由器自動給你過濾，只發給局域網主機
            String ip = "host:" + Dns.GetHostEntry(Dns.GetHostName()).AddressList.Last().ToString();//對外廣播本機的ip地址
            byte[] ipByte = Encoding.UTF8.GetBytes(ip);
            DispatcherTimer dt = new DispatcherTimer() { Interval = TimeSpan.FromSeconds(1) };//每隔1秒對外發送一次廣播
            dt.Tick += delegate
            {
                client.Send(ipByte, ipByte.Length, endpoint);
            };
            dt.Start();
        }

接收：

        void MainWindow_Loaded(object sender, RoutedEventArgs e)
        {
            Loaded -= MainWindow_Loaded;
            UdpClient client = new UdpClient(new IPEndPoint(IPAddress.Any, 7788));//端口要與發送端相同
            Thread thread = new Thread(receiveUdpMsg);//用線程接收，避免UI卡住
            thread.IsBackground = true;
            thread.Start(client);
        }
        void receiveUdpMsg(object obj)
        {
            UdpClient client = obj as UdpClient;
            IPEndPoint endpoint = new IPEndPoint(IPAddress.Any, 0);
            while (true)
            {
                client.BeginReceive(delegate(IAsyncResult result) {
                    Console.WriteLine(result.AsyncState.ToString());//委托接收消息
                }, Encoding.UTF8.GetString(client.Receive(ref endpoint)));
            }
        }

效果：