接收UDP廣播（C＃）的答案

Question

我試圖發送一個udp廣播，並在c＃中收到答案。雖然發送廣播的作品完美，我沒有收到任何答案在C＃中。但是，當我把使用Wireshark一看，我可以看到一個答案已發出：

1. 從192.168.0.141發送到192.168.0.255
2. 從192.168.0.105發送到255.255.255.255（這將是答案）

Wireshark的日誌：

1 0.000000 192.168.0.141 192.168.0.255 UDP Source port: 55487 Destination port: 17784 
2 0.000851 192.168.0.105 255.255.255.255 UDP Source port: 17784 Destination port: 55487 

這就是我的C＃代碼：調用udpClient.Receive時

private static byte[] SendBuffer = new byte[] { 1, 2, 3 }; 

    public static void SendAndReceiveBroadcast(byte[] data, IPEndPoint broadcastEndpoint) 
    { 

     using(Socket broadcastSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp)) 
     { 
      broadcastSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, 1); 
      broadcastSocket.SendTo(data, broadcastEndpoint); 
      receivePort = broadcastSocket.LocalEndPoint.ToString().Split(':')[1]; 
      Console.WriteLine("Sent {0} from Port {1}", CollectionsHelper.ItemsToString(data, "{0:X2}"), broadcastSocket.LocalEndPoint.ToString()); 
      broadcastSocket.Close(); 
     } 

     using(Socket receiveSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp)) 
     { 
      IPEndPoint broadcastAddress = new IPEndPoint(IPAddress.Any, Convert.ToInt32(receivePort)); 
      UdpClient udpClient = new UdpClient(); 
      udpClient.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true); 
      udpClient.Client.Bind(broadcastAddress); 
      IPEndPoint remoteIP = new IPEndPoint(IPAddress.Any, Convert.ToInt32(receivePort)); 
      byte[] answer = udpClient.Receive(ref remoteIP); 
     } 
    } 

程序停止。任何人都可以幫助我嗎？ :)

Answer 1

1. 您應該使用ReceiveFrom。 Receive用於TCP。
2. 如果我沒有弄錯，廣播消息不排隊。廣播前撥打BeginReceiveFrom，之後撥打EndReceiveFrom。

Answer 2

由於您使用相同的過程發送和接收，您需要在發送消息之前打開接收器，並且您需要使用udpClient.ReceiveAsync（）並等待答案，然後再允許您的程序去關機。