How to turn Windows.UI.Xaml.Media.Imaging.BitmapImage into byte[]

Question

Things are like this:

I have read a image file and I decoded it to show it in an Image(img).

Then I got the value of img.Source.

I want to save it into an database but at first I should turn the BitmapImage into byte[]. I've searched tens of articles but their answers are unusable since their BitmapImage is System.Windows.Media.Imaging.BitmapImage, not Windows.UI.Xaml.Media.Imaging.BitmapImage. I can't using System.Windows.Media cause seems there's no such a namespace in UWP.

Thus I can't use BitmapImage.StreamSource. Please help, thanks a lot!

Answer 1

Hi @水 知 ,

Welcome to Micrsoft Q&A!

It is recommended that you use RandomAccessStreamReference.CreateFromUri(Uri) to access BitmapImage.

The name of my image control is Testimg.

You can refer to the following code sample, hope it helps!

private void Image_Loaded(object sender, RoutedEventArgs e)
{

    Image img = sender as Image;
    BitmapImage bitmapImage = new BitmapImage();
    img.Width = bitmapImage.DecodePixelWidth = 80; //natural px width of image source
                                                    // don't need to set Height, system maintains aspect ratio, and calculates the other
                                                    // dimension, so long as one dimension measurement is provided
    bitmapImage.UriSource = new Uri(img.BaseUri, "Assets/StoreLogo.png");
    img.Source = bitmapImage;

}
private async void Button_Click(object sender, RoutedEventArgs e)
{
            
    BitmapImage bitmapImage= Testimg.Source as BitmapImage;
    RandomAccessStreamReference stream = RandomAccessStreamReference.CreateFromUri(bitmapImage.UriSource);
    var streamContent = await stream.OpenReadAsync();
    byte[] buffer = new byte[streamContent.Size];
    await streamContent.ReadAsync(buffer.AsBuffer(), (uint)streamContent.Size, InputStreamOptions.None);
          
}

<Image x:Name="Testimg" Loaded="Image_Loaded"  HorizontalAlignment="Left" Height="100" VerticalAlignment="Top" Width="100"/>

Thank you.

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