Re: Inheritance and MFC

From:
"Nobody" <Nobody@yahoo.com>
Newsgroups:
microsoft.public.vc.mfc
Date:
Tue, 3 Jul 2007 17:45:56 -0700
Message-ID:
<#KlqwSdvHHA.2068@TK2MSFTNGP06.phx.gbl>
Hi David,

You cannot use multiple inheritance with multiple CObject-derived =

bases.

Only the left-most base can derive from CObject.

I am not quite sure what you mean by that?
I believe that is what I am doing.

I think I need CWnd to implement Scrollbars, so that is why I am =
inheriting from CWnd.

I think what I am actually doing is creating a control that contains =
controls.

This is basically what I have.

CGrid : public CObject
{
   // Bunch of Stuff
}

CGridSB: public CGrid, public CWnd
{
    CScrollbar sb;
    CreateScrollbars();
    SetScreenRect(){ Position Scrollbars(); }
}

CView::OnDraw()
{
    CGridSB sb;
    sb.SetScreenRect(Rect);
    sb.OnDraw(pDC);
    // Instead of creating and adding scrollbars here, I just need to =
figure out
    // how to add the scrollbars to the grid object.
}

Thanks,
"David Wilkinson" <no-reply@effisols.com> wrote in message =
news:eKJEC0VvHHA.3364@TK2MSFTNGP02.phx.gbl...

Nobody wrote:

Hi,
 
I have a grid object. The Grid Object inherits from CObject.
There are no controls and I was thinking about adding some. Zoom, =

Pan, etc.

 
So, I have extantiated a new class that inherits from CGrid and CWnd.
class CGridSB : public CGrid, public CWnd
 
Now, I would like to add some controls to the Grid Object.
The problem is that the controls needs an m_hWnd
I am not sure what to do?
 
 VERIFY(c_sbHZoom.Create(
      SBS_VERT | SBS_RIGHTALIGN | WS_CHILD |WS_BORDER,
   Rect,
   this,
   1234)
 );
 
_AFXWIN_INLINE void CScrollBar::ShowScrollBar(BOOL bShow)
 { ASSERT(::IsWindow(m_hWnd)); ::ShowScrollBar(m_hWnd, SB_CTL, =

bShow); }

 
I understand that the CGridSB oject needs to handle the Scrollbar =

messages, so I need a message map

and perphaps a DECLARE_DYNCREATE along with an IMPLEMENT_DYNCREATE =

member.

 
Nobody:
 
You cannot use multiple inheritance with multiple CObject-derived =

bases.

Only the left-most base can derive from CObject.
 
--
David Wilkinson
Visual C++ MVP

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