WriteableBitmap _writeBitmap;
public async void ContinueFileOpenPicker(FileOpenPickerContinuationEventArgsargs)
{
      IRandomAccessStream fileStream;
      BitmapImage bitmapImage = new BitmapImage();
      if ((args.ContinuationData["Operation"] as string) == "Image" && args.Files != null && args.Files.Count > 0)
      {
            StorageFile file = args.Files[0];
            fileStream = await file.OpenAsync(Windows.Storage.FileAccessMode.Read);
            bitmapImage.SetSource(fileStream);
            _writeBitmap = new WriteableBitmap(bitmapImage);
            img.Source = bitmapImage;
       }

}

红色的报错： “Windows.UI.Xaml.Media.Imaging.WriteableBitmap”不包含采用“1”个参数的构造函数