Question

我正在尝试发送udp广播，并在c＃中收到答案。虽然发送广播完美，但我没有收到任何c＃的答案。但是当我看看wireshark时，我可以看到已经发送了答案：

从192.168.0.141发送到192.168.0.255
从192.168.0.105发送到255.255.255.255（这就是答案）

Wireshark日志：

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

这就是我的c＃代码：

    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 );
        }
    }

调用udpClient.Receive时程序停止。任何人都可以帮助我PLZ？：）

Answer 1

由于您使用相同的进程发送和接收，因此您需要在发送消息之前打开接收器，并且需要使用udpClient.ReceiveAsync（）并在允许程序关闭之前等待答案

Answer 2

您应该使用ReceiveFrom。 Receive用于TCP。
如果我没弄错的话，广播消息不会排队。广播前请致电BeginReceiveFrom，之后致电EndReceiveFrom。

接收UDP广播（C＃）的答案

2 个答案: