c# - 是否可以使 GattCharacteristic ValueChange 事件发生在多个设备上？

Question

This question和我的问题类似。但在我的情况下，我有不止一台设备想要为他们捕获更改事件。在字段级创建 GattCharacteristic 和 GattDeviceService 对象的实例解决了问题，但连接的设备数量应该是可变的。

 var devices = await DeviceInformation.FindAllAsync(GattDeviceService.GetDeviceSelectorFromUuid(new Guid("00002000-0000-1000-8000-00805f9b34fb")), null);
            for (int i = 0; i < devices.Count; i++)
            {

                GattDeviceService service= await GattDeviceService.FromIdAsync(devices[i].Id);
                GattCharacteristic characteristic = service.GetCharacteristics(new Guid("00002001-0000-1000-8000-00805f9b34fb")).FirstOrDefault();
                characteristic.ValueChanged += CounterCharacteristic_ValueChanged;
                await characteristic.WriteClientCharacteristicConfigurationDescriptorAsync(GattClientCharacteristicConfigurationDescriptorValue.Notify);
             }

如果我们像上面那样定义change事件一段时间后它停止运行。如何解决多台设备的问题？

Answer 1

在您的代码示例中，您添加了多个事件处理程序，这是您必须避免的事情。为了防止你可以这样做:

var devices = await   DeviceInformation.FindAllAsync(GattDeviceService.GetDeviceSelectorFromUuid(new Guid("00002000-0000-1000-8000-00805f9b34fb")), null);
            for (int i = 0; i<devices.Count; i++)
            {    
                GattDeviceService service = await GattDeviceService.FromIdAsync(devices[i].Id);
        GattCharacteristic characteristic = service.GetCharacteristics(new Guid("00002001-0000-1000-8000-00805f9b34fb")).FirstOrDefault();        
                await characteristic.WriteClientCharacteristicConfigurationDescriptorAsync(GattClientCharacteristicConfigurationDescriptorValue.Notify);
        AddValueChangedHandler(characteristic);
}

private bool isValueChangedHandlerRegistered = false;//make this a field!

 private void AddValueChangedHandler(GattCharacteristic selectedCharacteristic )
        {
            if (!isValueChangedHandlerRegistered)
            {
                selectedCharacteristic.ValueChanged += CounterCharacteristic_ValueChanged;
                isValueChangedHandlerRegistered = true;
            }
        }

在你的eventHandler中你可以通过

区分不同的设备

if (sender.Service.Device == bluetoothLeDevice_1) 
{
//do something
}
    if (sender.Service.Device == bluetoothLeDevice_2) 
{
//do something
}