How can I receive data from server by streamsocket continuously?

Question

I am a WPF programmer and now is a beginner of UWP.

I need to write a new program to connect a remote machine now. And the machine will send data to the client at times.

I wanna that whenever the machine sends the data, the client will get it at once.

In WPF I can use the Asynchronous Client Socket, whenever there is a data to the client, the ReceiveCallback will get it at once as shown in this example.

However, in UWP it seems has not the Asynchronous Client Socket. I used the SteamSocket to connect the remote machine successfully as below:

 Task.Run(async()=>{
                try
                {
                    StreamSocket SS = new StreamSocket();
                    await SS.ConnectAsync(new Windows.Networking.HostName("192.168.200.111"), "23");

                    DataWriter writer = new DataWriter(SS.OutputStream);
                    string content = "ST";
                    byte[] data = Encoding.UTF8.GetBytes(content);
                    writer.WriteBytes(data); 
                    await writer.StoreAsync();
                    writer.DetachStream();
                    writer.Dispose();

                    DataReader reader = new DataReader(SS.InputStream);
                    reader.InputStreamOptions = InputStreamOptions.Partial;
                    await reader.LoadAsync(1024);
                    string response = reader.ReadString(reader.UnconsumedBufferLength);
                    Debug.WriteLine(response);                       
                }
                catch(Exception ex)
                {
                    throw ex;
                }
            });

Whereas, these codes can only read the data when you use the DataReader, but not with an event to show it when received the data at once.

By using a loopback may solve it and I don't want the code being so ugly with the loopback.

I googled but found nothing useful about this.

I asked Microsoft engineer about this and he told me to use the SocketActivityTrigger, I don't want to use it for it not only hard to use but also is a background worker. Even I exit the UWP program it will still connect to the remote machine and receive the data continuously.

Would you please tell me how to solve it?

To @Nico Zhu:

 private void Button_Click(object sender, RoutedEventArgs e)
        {
            Task.Run(async()=>{
                try
                {                    
                    StreamSocketListener SSL = new StreamSocketListener();
                    SSL.ConnectionReceived += SSL_ConnectionReceived;
                    await SSL.BindEndpointAsync(new Windows.Networking.HostName("192.168.200.111"), "23");

                }
                catch(Exception ex)
                {
                    throw ex;
                }
            });
        }

        private void SSL_ConnectionReceived(StreamSocketListener sender, StreamSocketListenerConnectionReceivedEventArgs args)
        {
            Debug.WriteLine("123");
        }

I used the StreamSocketListener, but after I ran the program, it reports '

{System.Runtime.InteropServices.COMException (0x80072741): The requested address is not valid in its context

   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.GetResult()
   at App2.MainPage.<<Button_Click>b__2_0>d.MoveNext()}

' What's wrong with this?

@NicoZhu-MSFT I just update the question by using the StreamSocketListener you said, but it reports an error that'{System.Runtime.InteropServices.COMException (0x80072741): The requested address is not valid in its context'.What's wrong with this? Thank you. — 102425074, Nov 05 '18 at 08:03
@NicoZhu-MSFT I have checked that I have added the privateNetworkClientServer/Internet(Client & Server) / Internet(Client) capability. — 102425074, Nov 05 '18 at 08:23
@NicoZhu-MSFT I am sorry about that for it is a machine in the factory but not a remote server. I tried using the StreamSocket and it works. But strangely the StreamSocketListener not. — 102425074, Nov 05 '18 at 08:26
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/183111/discussion-between-nico-zhu-msft-and-102425074). — Nico Zhu, Nov 05 '18 at 08:32
@NicoZhu-MSFT I am making a client connect to the machine, now the problem is from the code of the client. What's more, our network is the Internal network, we can access the internet but others can not access our computer without using some tools like TeamViewer. — 102425074, Nov 05 '18 at 08:32
@NicoZhu-MSFT I found a strange way to solve it. Although it is not so perfect, please see the answer below. Thanks for helping me so much. — 102425074, Nov 07 '18 at 05:48
Perfect, you could mark it as accepted to convenient people who visit this thread later. — Nico Zhu, Nov 07 '18 at 05:54

score 1 · Accepted Answer · answered Nov 07 '18 at 05:47

Thanks for @Nico Zhu helping me so much. Finally, I found a strange way to do it: using the socket of WPF in UWP

But it is strange that the socket of WPF has not the Asynchronous Client Socket in UWP, so that I can only do it like this:

 await Task.Factory.StartNew(async () =>
            {
                IPEndPoint ip = new IPEndPoint(IPAddress.Parse("192.168.200.111"), 23);
                Socket S = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                S.Connect(ip);
                S.Send(Encoding.UTF8.GetBytes("SS" + Environment.NewLine));
                while (true)
                {
                    byte[] buffer = new byte[1024];
                    if (S.Available != 0)
                    {
                        S.Receive(buffer);
                        Debug.WriteLine(Encoding.UTF8.GetString(buffer));
                        Debug.WriteLine("");
                        await Task.Delay(100);
                    }
                }
            });

How can I receive data from server by streamsocket continuously?

1 Answers1