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CWnd::PreCreateWindow

Called by the framework before the creation of the Windows window attached to this CWnd object.

virtual BOOL PreCreateWindow(
   CREATESTRUCT& cs 
);

cs

A CREATESTRUCT structure.

Nonzero if the window creation should continue; 0 to indicate creation failure.

Caution noteCaution

CWnd::PreCreateWindow now assigns the hMenu member of cs to the this pointer if the menu is NULL and the style contains WS_CHILD. For proper functionality, ensure that your dialog control has an ID that is not NULL.

This change fixes a crash in managed/native interop scenarios. A TRACE statement in CWnd::Create alerts the developer of the problem.

Never call this function directly.

The default implementation of this function checks for a NULL window class name and substitutes an appropriate default. Override this member function to modify the CREATESTRUCT structure before the window is created.

Each class derived from CWnd adds its own functionality to its override of PreCreateWindow. By design, these derivations of PreCreateWindow are not documented. To determine the styles appropriate to each class and the interdependencies between the styles, you can examine the MFC source code for your application's base class. If you choose to override PreCreateWindow, you can determine whether the styles used in your application's base class provide the functionality you need by using information gathered from the MFC source code.

For more information on changing window styles, see the Changing the Styles of a Window Created by MFC.


// alter the styles of the mdi frame window
BOOL CMdiChildFrame::PreCreateWindow(CREATESTRUCT& cs)
{
   // Create a window without min/max buttons or sizable border
   cs.style |= WS_OVERLAPPED | WS_SYSMENU | WS_BORDER;

   // Size the window to 1/3 screen size and center it
   cs.cy = ::GetSystemMetrics(SM_CYSCREEN) / 3;
   cs.cx = ::GetSystemMetrics(SM_CXSCREEN) / 3;
   cs.y = ((cs.cy * 3) - cs.cy) / 2;
   cs.x = ((cs.cx * 3) - cs.cx) / 2;

   return CMDIChildWnd::PreCreateWindow(cs);
}


Header: afxwin.h

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