如何使用二维码扫描MediaCapture.VideoDeviceController控制UWP中摄像头的曝光或亮度

using Windows.Media.Capture;
using Windows.Media.Devices;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;

<CaptureElement x:Name="captureElement" />

private MediaCapture mediaCapture;

protected override async void OnNavigatedTo(NavigationEventArgs e)
{
    mediaCapture = new MediaCapture();
    await mediaCapture.InitializeAsync();

    captureElement.Source = mediaCapture;
    await mediaCapture.StartPreviewAsync();
}

private async void ScanQRCode()
{
    // 创建二维码扫描器
    BarcodeScanner scanner = new BarcodeScanner();

    // 设置扫描器的输入源为摄像头
    scanner.VideoDeviceController = mediaCapture.VideoDeviceController;

    // 启动扫描器
    BarcodeScannerResult result = await scanner.ScanAsync();

    if (result != null)
    {
        // 获取扫描结果
        string barcode = result.Text;

        // 根据扫描结果进行曝光或亮度的调整
        if (barcode == "曝光")
        {
            // 获取摄像头的曝光控制器
            var exposure = mediaCapture.VideoDeviceController.Exposure;

            // 调整曝光值
            exposure.Value = exposure.Capabilities.Max;
        }
        else if (barcode == "亮度")
        {
            // 获取摄像头的亮度控制器
            var brightness = mediaCapture.VideoDeviceController.Brightness;

            // 调整亮度值
            brightness.Value = brightness.Capabilities.Max;
        }
    }
}

private void ScanButton_Click(object sender, RoutedEventArgs e)
{
    ScanQRCode();
}