Windows IoT Raspberry Pi 3 C＃USB DeviceWatcher

Question

我设法枚举我的USB设备，如下所示。如何将enumerateDevices添加到DeviceWatcher中？ 我参考了以下示例，但仍未取得任何进展。 观察者在启动期间确实触发了一次，随后我的usb设备中的任何更改都没有显示任何内容。

[如果添加，删除或更改设备（XAML）如何获取通知] [1]  [设备枚举样本] [2]知道如何持续监控USB端口上的更改，以提示是否有任何USB设备被移除或连接？

private void StartWatcher()
    {
        usbStorageWatcher = DeviceInformation.CreateWatcher(DeviceClass.PortableStorageDevice);
        audioCaptureWatcher = DeviceInformation.CreateWatcher(DeviceClass.AudioCapture);
        audioRenderWatcher = DeviceInformation.CreateWatcher(DeviceClass.AudioRender);

        usbStorageWatcherAdded = new TypedEventHandler<DeviceWatcher, DeviceInformation>(async (watcher, deviceInfo) =>
        {
            await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Low, async () =>
            {
                var usbDevices = await DeviceInformation.FindAllAsync(DeviceClass.PortableStorageDevice);
                if (usbDevices.Count > 0)
                {
                    for (var i = 0; i < usbDevices.Count; i++)
                    {
                        usbDeviceList.Add(usbDevices[i]);
                    }
                    usbList.SelectedItem = usbDevices[0];
                    usbDeviceCount.Text = usbDevices.Count.ToString();
                    GeneralMessage.Text = String.Format("{0} USB Storage found.", usbDevices.Count);
                }


            });
        });
        usbStorageWatcher.Added += usbStorageWatcherAdded;

usbStorageWatcherRemoved = new TypedEventHandler<DeviceWatcher, DeviceInformationUpdate>(async (watcher, deviceInfoUpdate) =>
        {
            await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Low, async () =>
            {
                var usbDevices = await DeviceInformation.FindAllAsync(DeviceClass.PortableStorageDevice);
                if (usbDevices.Count > 0)
                {
                    for (var i = 0; i < usbDevices.Count; i++)
                    {
                        usbDeviceList.Add(usbDevices[i]);
                    }
                    usbList.SelectedItem = usbDevices[0];
                    usbDeviceCount.Text = usbDevices.Count.ToString();
                    GeneralMessage.Text = String.Format("{0} USB Storage found.", usbDevices.Count);
                }

            });
        });
        usbStorageWatcher.Removed += usbStorageWatcherRemoved;