c# - 如何正确接收 UDP 数据报包？

Question

我正在设置一个 Windows 服务，它只是打开一个 UDP 端口并将接收到的任何内容打印到日志文件中。然而，我的问题是，当服务打开端口时，我从来没有收到任何东西。我正在从 UDP 发送者 android 应用程序发送 UDP 数据包。发送数据包的电话在我的家庭 Wi-fi 网络上（以及运行该服务的电脑）。服务名称是 myShutdownService。我已经尝试停止并再次启动服务，但这没有帮助。

服务.cs代码：

namespace myShutdownService
{
    public partial class Service1 : ServiceBase
    {
        public Service1()
        {
            InitializeComponent();

            UDPSocket s = new UDPSocket();
            string ip = UDPSocket.GetLocalIPAddress();
            int port = 2700;

            s.Server(ip, port);
            s.WriteToFile("Opening server socket on  " + ip + ":" + port );

        }

        protected override void OnStart(string[] args)
        {
        }

        protected override void OnStop()
        {
            UDPSocket s = new UDPSocket();
            s.WriteToFile(" STOPPING SERVICE");
        }
    }
}

我的 UDP 套接字类：

namespace myShutdownService
{
    public class UDPSocket
    {
        private Socket _socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
        private const int bufSize = 8 * 1024;
        private State state = new State();
        private EndPoint epFrom = new IPEndPoint(IPAddress.Any, 0);
        private AsyncCallback recv = null;

        public class State
        {
            public byte[] buffer = new byte[bufSize];
        }

        public static string GetLocalIPAddress()
        {
            var host = Dns.GetHostEntry(Dns.GetHostName());
            foreach (var ip in host.AddressList)
            {
                if (ip.AddressFamily == AddressFamily.InterNetwork)
                {
                    return ip.ToString();
                }
            }
            throw new Exception("No network adapters with an IPv4 address in the system!");
        }

        public void Server(string address, int port)
        {
            _socket.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.ReuseAddress, true);
            _socket.Bind(new IPEndPoint(IPAddress.Parse(address), port));
            Receive();
        }

        public void Client(string address, int port)
        {
            _socket.Connect(IPAddress.Parse(address), port);
            Receive();
        }

        public void Send(string text)
        {
            byte[] data = Encoding.ASCII.GetBytes(text);
            _socket.BeginSend(data, 0, data.Length, SocketFlags.None, (ar) =>
            {
                State so = (State)ar.AsyncState;
                int bytes = _socket.EndSend(ar);
                WriteToFile("SEND: " + text);
            }, state);
        }

        private void Receive()
        {
            _socket.BeginReceiveFrom(state.buffer, 0, bufSize, SocketFlags.None, ref epFrom, recv = (ar) =>
            {
                State so = (State)ar.AsyncState;
                int bytes = _socket.EndReceiveFrom(ar, ref epFrom);
                _socket.BeginReceiveFrom(so.buffer, 0, bufSize, SocketFlags.None, ref epFrom, recv, so);
                WriteToFile("RECV: " + epFrom.ToString() + " message: " + Encoding.ASCII.GetString(so.buffer, 0, bytes));
            }, state);
        }

        public void WriteToFile(string Message)
        {
            string path = AppDomain.CurrentDomain.BaseDirectory + "\\Logs";
            if (!Directory.Exists(path))
            {
                Directory.CreateDirectory(path);
            }
            string filepath = AppDomain.CurrentDomain.BaseDirectory + "\\Logs\\ServiceLog_" + DateTime.Now.Date.ToShortDateString().Replace('/', '_') + ".txt";
            if (!File.Exists(filepath))
            {
                // Create a file to write to.   
                using (StreamWriter sw = File.CreateText(filepath))
                {
                    sw.WriteLine(Message);
                }
            }
            else
            {
                using (StreamWriter sw = File.AppendText(filepath))
                {
                    sw.WriteLine(Message);
                }
            }
        }
    }
}

日志文件输出：

Opening server socket on  192.168.56.1:2700
 STOPPING SERVICE
Opening server socket on  192.168.56.1:2700

我的 Windows 资源监视器

我的 ipconfig

我的 Windows 服务管理器

标签： c#windowsservice