public sealed partial class Scanner2 : Page
    {
        private readonly MediaCapture _mediaCapture = new MediaCapture();
        private Result _result;

        public Scanner2()
        {
            InitializeComponent();
        }

        protected override async void OnNavigatedTo(NavigationEventArgs e)
        {
            try
            {
                var cameras = await DeviceInformation.FindAllAsync(DeviceClass.VideoCapture);
                if (cameras.Count < 1)
                {
                    throw new NoCameraAvailableException();
                }
                MediaCaptureInitializationSettings settings;
                if (cameras.Count == 1)
                {
                    settings = new MediaCaptureInitializationSettings {VideoDeviceId = cameras[0].Id};
                }
                else
                {
                    DeviceInformation backWebcam = (from webcam in cameras
                                                    where webcam.EnclosureLocation != null
                                                    && webcam.EnclosureLocation.Panel == Windows.Devices.Enumeration.Panel.Back
                                                    select webcam).FirstOrDefault();

                    settings = new MediaCaptureInitializationSettings {VideoDeviceId = backWebcam.Id};
                }

                await _mediaCapture.InitializeAsync(settings);
                VideoCapture.Source = _mediaCapture;
                await _mediaCapture.StartPreviewAsync();

                var focusSetting = new FocusSettings
                {
                    Mode = FocusMode.Continuous,
                    AutoFocusRange = AutoFocusRange.Normal,
                    DisableDriverFallback = false,
                    WaitForFocus = true
                };

                _mediaCapture.VideoDeviceController.FocusControl.Configure(focusSetting);
                await _mediaCapture.VideoDeviceController.ExposureControl.SetAutoAsync(true);

                _mediaCapture.SetPreviewRotation(VideoRotation.Clockwise90Degrees);
                _mediaCapture.VideoDeviceController.FlashControl.Enabled = false;

                while (_result == null)
                {
                    using (var stream = new InMemoryRandomAccessStream())
                    {
                        await _mediaCapture.CapturePhotoToStreamAsync(ImageEncodingProperties.CreateJpeg(), stream);

                        stream.Seek(0);

                        var writeableBitmap = new WriteableBitmap(1, 1);
                        await writeableBitmap.SetSourceAsync(stream);

                        _result = ScanBitmap(writeableBitmap);
                    }
                }

                await _mediaCapture.StopPreviewAsync();
                VideoCapture.Visibility = Visibility.Collapsed;
                CaptureImage.Visibility = Visibility.Visible;

                Debug.WriteLine("Scanned text: {0}", _result.Text);
                Frame.GoBack();
            }
            catch (UnauthorizedAccessException ex)
            {

            }
            catch (NoCameraAvailableException ex)
            {

            }
            catch (Exception ex)
            {

            }
        }

        private Result ScanBitmap(WriteableBitmap writeableBmp)
        {
            var barcodeReader = new BarcodeReader
            {
                Options = new DecodingOptions
                {
                    PossibleFormats = new[] { BarcodeFormat.QR_CODE },
                    TryHarder = true
                },
                AutoRotate = true
            };
            var result = barcodeReader.Decode(writeableBmp);

            if (result != null)
            {
                CaptureImage.Source = writeableBmp;
            }

            return result;
        }

        protected override async void OnNavigatingFrom(NavigatingCancelEventArgs e)
        {
            await _mediaCapture.StopPreviewAsync();
        }
    }