地铁应用程序的条形码扫描仪

查看CodePlex和NuGet上的ZXing.Net。CodePlex源代码有WinRT应用程序的示例。

主页.xaml

<Grid Background="{StaticResource ApplicationPageBackgroundThemeBrush}">
  <Canvas Width="640" Height="360">
     <CaptureElement x:Name="VideoCapture" Width="640" Height="360" />
     <Image x:Name="CaptureImage" Width="640" Height="360" Visibility="Collapsed" />
  </Canvas>
  <TextBlock x:Name="Error" VerticalAlignment="Bottom" FontSize="32" Width="640" TextAlignment="Center" Margin="363,0,363,37" />
  <TextBlock x:Name="ScanResult" VerticalAlignment="Bottom" TextAlignment="Center" FontSize="32" Width="640"/>
</Grid>

主页.xaml.cs

public sealed partial class MainPage : Page
{
  private readonly MediaCapture _mediaCapture = new MediaCapture();
  private Result _result;
  public MainPage()
  {
     InitializeComponent();
  }
  protected override async void OnNavigatedTo(NavigationEventArgs e)
  {
     try
     {
        var cameras = await DeviceInformation.FindAllAsync(DeviceClass.VideoCapture);
        if (cameras.Count < 1)
        {
           Error.Text = "No camera found, decoding static image";
           await DecodeStaticResource();
           return;
        }
        MediaCaptureInitializationSettings settings;
        if (cameras.Count == 1)
        {
           settings = new MediaCaptureInitializationSettings { VideoDeviceId = cameras[0].Id }; // 0 => front, 1 => back
        }
        else
        {
           settings = new MediaCaptureInitializationSettings { VideoDeviceId = cameras[1].Id }; // 0 => front, 1 => back
        }
        await _mediaCapture.InitializeAsync(settings);
        VideoCapture.Source = _mediaCapture;
        await _mediaCapture.StartPreviewAsync();
        while (_result == null)
        {
           var photoStorageFile = await KnownFolders.PicturesLibrary.CreateFileAsync("scan.jpg", CreationCollisionOption.GenerateUniqueName);
           await _mediaCapture.CapturePhotoToStorageFileAsync(ImageEncodingProperties.CreateJpeg(), photoStorageFile);
           var stream = await photoStorageFile.OpenReadAsync();
           // initialize with 1,1 to get the current size of the image
           var writeableBmp = new WriteableBitmap(1, 1);
           writeableBmp.SetSource(stream);
           // and create it again because otherwise the WB isn't fully initialized and decoding
           // results in a IndexOutOfRange
           writeableBmp = new WriteableBitmap(writeableBmp.PixelWidth, writeableBmp.PixelHeight);
           stream.Seek(0);
           writeableBmp.SetSource(stream);
           _result = ScanBitmap(writeableBmp);
           await photoStorageFile.DeleteAsync(StorageDeleteOption.PermanentDelete);
        }
        await _mediaCapture.StopPreviewAsync();
        VideoCapture.Visibility = Visibility.Collapsed;
        CaptureImage.Visibility = Visibility.Visible;
        ScanResult.Text = _result.Text;
     }
     catch (Exception ex)
     {
        Error.Text = ex.Message;
     }
  }
  private async System.Threading.Tasks.Task DecodeStaticResource()
  {
     var file = await Windows.ApplicationModel.Package.Current.InstalledLocation.GetFileAsync(@"Assets'1.jpg");
     var stream = await file.OpenReadAsync();
     // initialize with 1,1 to get the current size of the image
     var writeableBmp = new WriteableBitmap(1, 1);
     writeableBmp.SetSource(stream);
     // and create it again because otherwise the WB isn't fully initialized and decoding
     // results in a IndexOutOfRange
     writeableBmp = new WriteableBitmap(writeableBmp.PixelWidth, writeableBmp.PixelHeight);
     stream.Seek(0);
     writeableBmp.SetSource(stream);
     CaptureImage.Source = writeableBmp;
     VideoCapture.Visibility = Visibility.Collapsed;
     CaptureImage.Visibility = Visibility.Visible;
     _result = ScanBitmap(writeableBmp);
     if (_result != null)
     {
        ScanResult.Text += _result.Text;
     }
     return;
  }
  private Result ScanBitmap(WriteableBitmap writeableBmp)
  {
     var barcodeReader = new BarcodeReader
     {
        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();
  }
}