Weird WriteableBitmap FromStream issue

Question

I am desperately trying to load a WriteableBitmap with the FromStream extension method.

The code below throws a System.InvalidOperationException at the FromStream() call with the following information:

BitmapImage has not been initialized. Call the BeginInit method, set the appropriate properties, and then call the EndInit method.

I verified that the image exists and it's build action is set to Resource. The image is valid (I loaded it into a BitmapImage) and the stream has the correct length.

var sri = Application.GetResourceStream(new Uri("dummy.jpg", UriKind.RelativeOrAbsolute));
if (sri != null)
{
    using (var stream = sri.Stream)
    {
        // creates the bitmap, part of the writeablebitmapextensions on WPF
        var wb = BitmapFactory.New(1, 1); 
        wb.FromStream(stream); // <--- Exception
    }
}

The error seems to indicate the extension method uses a BitmapImage internally in an incorrect way, which I find hard to belive. I'm using WriteableBitmapEx.Wpf 1.0.14.0

What could be causing this exception? There is no other code running in my application.

score 2 · Accepted Answer · answered Mar 16 '15 at 19:33

The FromStream method in WriteableBitmapConvertExtensions.cs, line 367, seems to be broken. It is missing the BeginInit and EndInit calls on the BitmapImage:

public static WriteableBitmap FromStream(this WriteableBitmap bmp, Stream stream)
{
    var bmpi = new BitmapImage();
#if SILVERLIGHT
    bmpi.SetSource(stream);
    bmpi.CreateOptions = BitmapCreateOptions.None;
#elif WPF
    bmpi.StreamSource = stream;
#endif
    bmp = new WriteableBitmap(bmpi);
    return bmp;
}

It should look like this:

public static WriteableBitmap FromStream(this WriteableBitmap bmp, Stream stream)
{
    var bmpi = new BitmapImage();
#if SILVERLIGHT
    bmpi.SetSource(stream);
    bmpi.CreateOptions = BitmapCreateOptions.None;
#elif WPF
    bmpi.BeginInit();
    bmpi.StreamSource = stream;
    bmpi.EndInit();
#endif
    bmp = new WriteableBitmap(bmpi);
    return bmp;
}

Weird WriteableBitmap FromStream issue

1 Answers1