MFC CWindow Handles in C#

Hello,

I am trying to use an MFC/Direct Draw based DLL in my c# application. It is not a COM control but rather creates a CWindow based object to perform it's rendering on. It should essentially acted like a panel, or picture box that I would be able to put in a tabpage.

The interface to this DLL is a few simple C style entry points including a "create_window" type function. This function takes a window handle as the parent window for the new window.

I have a simple static c# class that uses p/invoke to call directly into this entry point. I use it like this:

FancyPInvoke.createWindow(this.tabPage1.Handle);

My problem is I can't seem to create a valid parent handle for my dll. Inside the dll if I use something like the following everything works (however, I get some disjoint window that isn't part of my app :( )

create_cwnd(hParentFromPInvoke, WS_POPUPWINDOW|WS_THICKFRAME);

My problem is when I try to create a window that will "sit" in a panel in my app.

create_cwnd(hParentFromPInvoke, WS_CHILD | WS_VISIBLE );