CWnd::GetTopWindow
CWnd*GetTopWindow()const;
Return Value
Identifies the top-level child window in a CWnd linked list of child windows. If no child windows exist, the value is NULL.
The returned pointer may be temporary and should not be stored for later use.
Remarks
Searches for the top-level child window that belongs to CWnd. If CWnd has no children, this function returns NULL.