Bluetooth RfcommService

Question

I've two devices running Windows on them; a Raspberry PI 3B + with Windows 10 IoT and a Surface pro with Windows 10. Now, I'm attempting to establish a communication between the two. 

Here's my server at the Raspberry Pi:

private readonly Guid _rfcommChatServiceUuid = Guid.Parse("34B1CF4D-1069-4AD6-89B6-E161D79BE4D8");

private async void CreateServer()
    {
        _provider = await RfcommServiceProvider.CreateAsync(RfcommServiceId.FromUuid(_rfcommChatServiceUuid));
        _listener = new StreamSocketListener();

        _listener.ConnectionReceived += OnConnectionReceived;
        await _listener.BindServiceNameAsync(_provider.ServiceId.AsString(),SocketProtectionLevel.BluetoothEncryptionAllowNullAuthentication);

        InitializeServiceSdpAttributes(_provider);
        _provider.StartAdvertising(_listener);
    }

    const uint SERVICE_VERSION_ATTRIBUTE_ID = 0x0300;
    const byte SERVICE_VERSION_ATTRIBUTE_TYPE = 0x0A;   // UINT32
    const uint SERVICE_VERSION = 200;
    void InitializeServiceSdpAttributes(RfcommServiceProvider provider)
    {
        var writer = new DataWriter();
        writer.WriteByte(SERVICE_VERSION_ATTRIBUTE_TYPE);
        writer.WriteUInt32(SERVICE_VERSION);
        var data = writer.DetachBuffer();
        provider.SdpRawAttributes.Add(SERVICE_VERSION_ATTRIBUTE_ID, data);
    }

 async void OnConnectionReceived(
StreamSocketListener listener,
StreamSocketListenerConnectionReceivedEventArgs args)
    {

        _provider.StopAdvertising();
        _listener.Dispose();
        _listener = null;
        _socket = args.Socket;

And, here's my client at the Surface Pro:

   var services = await DeviceInformation.FindAllAsync(
              RfcommDeviceService.GetDeviceSelector(RfcommServiceId.FromUuid(_rfcommChatServiceUuid)));

I don't understand why the services collection is still empty, can anyone tell me what's going on here?

Answer 1

Hard code the address on your client side. Here's the  RFCOMM connections' C code for both server and client: https://people.csail.mit.edu/albert/bluez-intro/x502.html

Also, here's a chat sample of Bluetooth RFCOMM for Windows(universal), that you can check out.