在windows8中bitmapimage和字節數組之間的轉換

Question

我寫下面的代碼將圖像轉換爲字節數組並稍後轉換回來，但它不起作用。任何人都可以幫忙

FileOpenPicker picker = new FileOpenPicker(); 
     picker.ViewMode = PickerViewMode.Thumbnail; 
     picker.SuggestedStartLocation = PickerLocationId.PicturesLibrary; 
     picker.FileTypeFilter.Add(".jpg"); 
     picker.FileTypeFilter.Add(".png"); 
     StorageFile file = await picker.PickSingleFileAsync(); 
     byte[] pixeByte; 
     using (IRandomAccessStream stream = await file.OpenReadAsync()) 
     { 
      WriteableBitmap image = new WriteableBitmap(400, 250); 
      image.SetSource(stream); 
      testImage.Source = image; 
      BitmapDecoder decoder = await BitmapDecoder.CreateAsync(stream); 
      BitmapTransform transform = new BitmapTransform(); 
      transform.ScaledWidth = 400; 
      transform.ScaledHeight = 250; 
      PixelDataProvider pixeldata =await decoder.GetPixelDataAsync(BitmapPixelFormat.Bgra8, BitmapAlphaMode.Straight, transform, ExifOrientationMode.IgnoreExifOrientation, ColorManagementMode.DoNotColorManage); 
      pixeByte = pixeldata.DetachPixelData(); 
     } 

     using (InMemoryRandomAccessStream stream = new InMemoryRandomAccessStream()) 
     { 
      BitmapImage image = new BitmapImage(); 
      await stream.WriteAsync(pixeByte.AsBuffer()); 
      stream.FlushAsync().AsTask().Wait(); 
      stream.Seek(0); 
      image.SetSource(stream); 
      testImage2.Source = image; 
     } 

解決：

public static async Task<byte[]> ImageToByteArrayAsync(StorageFile file) 
    { 
     using (IRandomAccessStream stream = await file.OpenReadAsync()) 
     {     
      using (DataReader reader = new DataReader(stream.GetInputStreamAt(0))) 
      { 
       await reader.LoadAsync((uint)stream.Size); 
       byte[] pixeByte = new byte[stream.Size]; 
       reader.ReadBytes(pixeByte); 
       return pixeByte; 
      } 
     } 
    } 

    // Convert a byte array to BitmapImage 
    public static async Task<BitmapImage> ByteArrayToImageAsync(byte[] pixeByte) 
    { 
     using (InMemoryRandomAccessStream stream = new InMemoryRandomAccessStream()) 
     { 
      BitmapImage image = new BitmapImage(); 
      await stream.WriteAsync(pixeByte.AsBuffer()); 
      stream.Seek(0); 
      image.SetSource(stream); 
      return image; 
     } 
    } 

Answer 1

我已經退出了部分我用一個流轉換爲字節數組： -

public async Task<byte[]> ImageToBytes(IRandomAccessStream sourceStream) 
{ 
    byte[] imageArray; 

    BitmapDecoder decoder = await BitmapDecoder.CreateAsync(sourceStream); 

    var transform = new BitmapTransform { ScaledWidth = decoder.PixelWidth, ScaledHeight = decoder.PixelHeight}; 
    PixelDataProvider pixelData = await decoder.GetPixelDataAsync(
     BitmapPixelFormat.Rgba8, 
     BitmapAlphaMode.Straight, 
     transform, 
     ExifOrientationMode.RespectExifOrientation, 
     ColorManagementMode.DoNotColorManage); 

    using (var destinationStream = new InMemoryRandomAccessStream()) 
    { 
     BitmapEncoder encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.PngEncoderId, destinationStream); 
     encoder.SetPixelData(BitmapPixelFormat.Rgba8, BitmapAlphaMode.Premultiplied, decoder.PixelWidth, 
           decoder.PixelHeight, 96, 96, pixelData.DetachPixelData()); 
     await encoder.FlushAsync(); 

     BitmapDecoder outputDecoder = await BitmapDecoder.CreateAsync(destinationStream); 
     await destinationStream.FlushAsync(); 
     imageArray = (await outputDecoder.GetPixelDataAsync()).DetachPixelData(); 
    } 
    return imageArray; 
} 

給一個嘗試，看看它的工作原理爲你而出。