How to convert Image.Source to byte array?

Question

My WP7 app has an Image control whose Source is set in XAML to an image with its Build Action set to Content:

<Image x:Name="MyImage" Source="/Images/myimage.png"/>

I need to store this image in my SqlCe database as a byte array. This is my current code to convert to byte[]:

public byte[] ImageToArray() {
    BitmapImage image = new BitmapImage();
    image.CreateOptions = BitmapCreateOptions.None;
    image.UriSource = new Uri( "/Images/myimage.png", UriKind.Relative );
    WriteableBitmap wbmp = new WriteableBitmap( image );
    return wbmp.ToArray();
}

The byte array saves to the database, but when I retrieve and my converter tries to convert it back (on a different page), I get "unspecified error." This is my converter:

public class BytesToImageConverter : IValueConverter {
    public object Convert( object Value, Type TargetType, object Parameter, CultureInfo Culture ) {
        if( Value != null && Value is byte[] ) {
            byte[] bytes = Value as byte[];

            using( MemoryStream stream = new MemoryStream( bytes ) ) {
                stream.Seek( 0, SeekOrigin.Begin );

                BitmapImage image = new BitmapImage();
                image.SetSource( stream ); // Unspecified error here
                return image;
            }
        }

        return null;
    }

    public object ConvertBack( object Value, Type TargetType, object Parameter, CultureInfo Culture ) {
        throw new NotImplementedException( "This converter only works for one way binding." );
    }
}

I've done quite a bit of searching. As far as the converter, my code is pretty standard. I've seen mention that stream.Position = 0; is necessary, but my understanding is stream.Seek is doing the same thing; I've tried both.

As my converter is the same I've used in about a dozen projects now, I'm fairly convinced the problem lies in converting the Image control's Source to a byte array and thus my image data is corrupted. In the code above I'm hard coding the Uri, but I've also tried

BitmapImage image = MyImage.Source as BitmapImage;

without luck. I've been at this for hours and at my wit's end. What am I missing?

Answer 1

I think the problem is in your ImageToArray() method. You are converting your WriteableBitmap object to array, but not the image itself. Try by replacing your method with the following:

    public byte[] ImageToArray()
    {
        BitmapImage image = new BitmapImage();
        image.CreateOptions = BitmapCreateOptions.None;
        image.UriSource = new Uri("/Images/myimage.png", UriKind.Relative);
        WriteableBitmap wbmp = new WriteableBitmap(image);
        MemoryStream ms = new MemoryStream();
        wbmp.SaveJpeg(ms, wbmp.PixelWidth, wbmp.PixelHeight, 0, 100);
        return ms.ToArray();
    }

This methd writes the image to a stream as jpg, and returns it bytes. I haven't tried the code, but you shouldn't have problem to convert it back to a BitmapImage using your converter.

Answer 2

The byte[] from image.UriSource may be base64 radix.You can browse byte[] or data in the SQL tale. If radix is wrong,can not reverse to stream from byte[].So if radix is 64,must convert to 16 radix.