C#发送和接收广播

public void sendBroadcast(string msg,int port)
        {
            Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
            IPEndPoint iep = new IPEndPoint(IPAddress.Broadcast, port);
            byte[] data = Encoding.UTF8.GetBytes(msg);
            sock.SetSocketOption(SocketOptionLevel.Socket,
                       SocketOptionName.Broadcast, 1);
            sock.SendTo(data, iep);
            sock.Close();
        }

        public void receiveBroadcast()
        {
            Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);

            IPEndPoint iep = new IPEndPoint(IPAddress.Any, 56789);

            EndPoint ep = (EndPoint)iep;

            socket.Bind(iep);

            while (true)
            {
                byte[] buffer = new byte[1024];

                socket.ReceiveFrom(buffer, ref ep);

                MessageBox.Show(Encoding.UTF8.GetString(buffer));

            }
        }