Topic: Image. FromHbitmap (IntPtr hbitmap)

Help please.

There is all a familiar method:

public static Bitmap System. Drawing. Image. FromHbitmap (IntPtr hbitmap) 

Where hbitmap it is a descriptor of bitmap GDI.

Question in the following: what is this descriptor (the structure on which it can eat what  specifies)?

The question has been caused by that that if to use  function for WPF:

        private static System.Windows.Media.Imaging.BitmapSource loadBitmap (System. Drawing. Bitmap source) 
            IntPtr ip = source. GetHbitmap (); 
            System.Windows.Media.Imaging.BitmapSource bs = null; 
                bs = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap (ip, 
                   IntPtr. Zero, System. Windows. Int32Rect. Empty, 
                   System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions ()); 
                GDI32.DeleteDC (ip); 

            return bs; 

And to try to display a desktop screenshot icons and buttons are displayed only: to close, tear and contract, and all remaining - a white background. In case of Image. FromHbitmap (IntPtr hbitmap) all is displayed correctly.