[GameWindow] Retrieve window handle

The window handle is not exposed, as it is an implementation detail. Even if it were part of the public API, you'd still need the display connection, device context or a number of other platform-specific parameters, which would still not be exposed.

OpenTK itself relies on IWindowInfo instances that contain all the necessary parameters. GameWindow provides a WindowInfo property that can be used with other OpenTK APIs (e.g. the GraphicsContext constructor).

Of course, this doesn't help if you need the handle for a non-OpenTK API. To that end, I must ask: what do you need the handle for?

I found how to retrieve the window handle...
if someone needs this:

IWindowInfo ii = ((OpenTK.NativeWindow)this).WindowInfo;
object inf = ((OpenTK.NativeWindow)this).WindowInfo;
PropertyInfo pi = (inf.GetType()).GetProperty("WindowHandle");
IntPtr hnd = ((IntPtr)pi.GetValue(ii, null));