Re: CS_HREDRAW | CS_VREDRAW

From:
Ajay Kalra <ajaykalra@yahoo.com>
Newsgroups:
microsoft.public.vc.mfc
Date:
30 Apr 2007 07:54:42 -0700
Message-ID:
<1177944882.768926.322270@n59g2000hsh.googlegroups.com>
On Apr 30, 7:55 am, "Zvuk" <remove percent signs from n%5%%@m%i%m-sra
%ga.hr> wrote:

In a MDI application (I don't know if it would be the same in a SDI
application), when I resize a child frame, it's content (I have some drawing
code in OnDraw) flicker. The issue is very simply solved in a pure Win32
application. You just put:

wndClass.style = 0;

instead of

wndClass.style = CS_HREDRAW | CS_VREDRAW;

But it does not seem that simple here. I have overriden the Create method, so I
have:

BOOL CChildFrame::Create(LPCTSTR lpszClassName, LPCTSTR lpszWindowName, DWORD
dwStyle , const RECT& rect , CMDIFrameWnd* pParentWnd , CCreateContext*
pContext)
{
return CMDIChildWnd::Create(AfxRegisterWndClass(0), lpszWindowName, dwStyle,
rect, pParentWnd, pContext);

}

But I could as well have had:

...
return CMDIChildWnd::Create(AfxRegisterWndClass(CS_HREDRAW | CS_VREDRAW),
lpszWindowName, dwStyle, rect, pParentWnd, pContext);
...

It still flickers, as if CS_HREDRAW | CS_VREDRAW were allready there and I could
not
get rid of them.

The very concept of overriding the Create method works indeed. If I for example
have:

...
return CMDIChildWnd::Create(AfxRegisterWndClass(CS_NOCLOSE), lpszWindowName,
dwStyle, rect, pParentWnd, pContext);
...

I really get a child window with the X on the title bar dimmed.

But it seems I can't get rid of CS_HREDRAW | CS_VREDRAW.

Why??


IIRC, CS_HREDRAW etc are added automatically by MFC. You can register
your window class in PreCreateWindow:

BOOL CMyMDIChildFrame::PreCreateWindow(CREATESTRUCT& cs)
{
   cs.lpszClass = AfxRegisterWndClass(
      CS_DBLCLKS, // if you need double-clicks
      NULL, // no cursor (use default)
      NULL, // no background brush
      AfxGetApp()->LoadIcon(IDC_YOURICON));
   ASSERT(cs.lpszClass);

   return CMDIChildWnd::PreCreateWindow(cs);
}

---
Ajay

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