Convert System.Drawing.Icon to System.Media.ImageSource

Question

I've got an IntPtr marshaled across an unmanaged/managed boundary that corresponds to an Icon Handle. Converting it to an Icon is trivial via the FromHandle() method, and this was satisfactory until recently.

Basically, I've got enough thread weirdness going on now that the MTA/STA dance I've been playing to keep a hosted WinForm from breaking the primary (WPF-tastic) UI of the application is too brittle to stick with. So the WinForm has got to go.

So, how can I get an ImageSource version of an Icon?

Note, I've tried ImageSourceConverter to no avail.

As an aside, I can get the underlying resource for some but not all of the icons involved and they generally exist outside of my application's assembly (in fact, they often exist in unmanaged dll's).

Answer 1

Try this:

Icon img;

Bitmap bitmap = img.ToBitmap();
IntPtr hBitmap = bitmap.GetHbitmap();

ImageSource wpfBitmap =
     Imaging.CreateBitmapSourceFromHBitmap(
          hBitmap, IntPtr.Zero, Int32Rect.Empty, 
          BitmapSizeOptions.FromEmptyOptions());

UPDATE: Incorporating Alex's suggestion and making it an extension method:

internal static class IconUtilities
{
    [DllImport("gdi32.dll", SetLastError = true)]
    private static extern bool DeleteObject(IntPtr hObject);

    public static ImageSource ToImageSource(this Icon icon)
    {            
        Bitmap bitmap = icon.ToBitmap();
        IntPtr hBitmap = bitmap.GetHbitmap();

        ImageSource wpfBitmap = Imaging.CreateBitmapSourceFromHBitmap(
            hBitmap,
            IntPtr.Zero,
            Int32Rect.Empty,
            BitmapSizeOptions.FromEmptyOptions());

        if (!DeleteObject(hBitmap))
        {
            throw new Win32Exception();
        }

        return wpfBitmap;
    }
}

Then you can do:

ImageSource wpfBitmap = img.ToImageSource();

Answer 2

MemoryStream iconStream = new MemoryStream();

myForm.Icon.Save(iconStream);

iconStream.Seek(0, SeekOrigin.Begin);

_wpfForm.Icon = System.Windows.Media.Imaging.BitmapFrame.Create(iconStream);

Answer 3

When using disposable streams it is almost always recommended to use 'using' blocks to force correct releasing of resources.

using (MemoryStream iconStream = new MemoryStream())
{
   icon.Save(iconStream);
   iconStream.Seek(0, SeekOrigin.Begin);

   this.TargetWindow.Icon = System.Windows.Media.Imaging.BitmapFrame.Create(iconStream);
}

Where icon is the source System.Drawing.Icon, and this.TargetWindow is the target System.Windows.Window.