GattCharacteristic.ValueChanged停止被调用

Question

I am attempting communication with an arduino using an Adafruit Bluefruit LE (a bluetooth 4 module), everything is set up and paired and all that, but I'm having trouble with the ValueChanged event on my GattCharacteristic, it stops firing after somewhere between 30 and 40 times.

Below is the setup code for this:

public class Bluetooth
{
    async public void Initialize()
    {
        var devices = await DeviceInformation.FindAllAsync(GattDeviceService.GetDeviceSelectorFromUuid(new Guid("6E400001-B5A3-F393-E0A9-E50E24DCCA9E")), null);

        GattDeviceService firstService = await GattDeviceService.FromIdAsync(devices[0].Id);

        GattCharacteristic rxCharacteristic = firstService.GetCharacteristics(new Guid("6E400003-B5A3-F393-E0A9-E50E24DCCA9E")).First();

        await rxCharacteristic.WriteClientCharacteristicConfigurationDescriptorAsync(GattClientCharacteristicConfigurationDescriptorValue.Notify);

        rxCharacteristic.ValueChanged += rxCharacteristicValueChanged;
    }

    private void rxCharacteristicValueChanged(GattCharacteristic characteristic, GattValueChangedEventArgs e)
    {
        Console.WriteLine(e.CharacteristicValue.ToArray()[6]);
    }
}

Is there some kind of buffer I need to clear or something like that? It doesnt look like its buffer related, because If I halve the data being sent, I dont get twice the calls, but I could be wrong. The Arduino reports that it is still sending data (through a serial link, I can see that the bluetooth library is still attempting to send data, at any rate. I am not sure how I would verify that the data is actually getting sent)

Any help would be appreciated, even suggestions on things to check.

Answer 1

Sounds GC related given your code.

Make firstService or something else a field-level instance.

Answer 2

This is scoping issue, it seems that the GattCharacteristic object is disposed of after an unknown amount of time...

Make your characteristic a global, problem solved.

"You may find that your application stops receiving updates from the device after a period of time. This is a scoping issue where objects are being disposed of that shouldn't. This is because the GattCharacteristic is disposed of before it should be, set the characteristic as a global rather than relying on it being copied in."