ActiveX Ctrl AND CMemDC flickerfree drawing

Hi,

I want to use the CMemDC class from codeproject:
http://www.codeproject.com/KB/GDI/flickerfree.aspx?msg 91984

to create a flickerfree drawing in the OnDraw of my ActiveX control.

I did what was descriped in the article about the CMemDC class.

I have:

void CchessCtrl::OnDraw(
            CDC* pdc, const CRect& rcBounds, const CRect& rcInvalid)
{
    if (!pdc)
        return;

    CMemDC pDC(pdc,&rcBounds);
    DrawBoard(pDC,rcBounds);

}

void CchessCtrl::DrawBoard(CDC* pdc, CRect o_rcBounds)
{
    BOOL b_Color;
    int n_Rank;
    int n_File;
    long n_rcBoundsHeight;
    long n_FieldHeight;
    long n_X;
    long n_Y;
    CBrush o_WhiteBrush;
    CBrush o_BlackBrush;
    CBrush* po_Brush;

    o_WhiteBrush.CreateSolidBrush(RGB(255,255,255));
    o_BlackBrush.CreateSolidBrush(RGB(0,0,0));

    n_rcBoundsHeight = o_rcBounds.Height ();
    n_FieldHeight = (long) ceil((double)n_rcBoundsHeight / 8.0);
    n_Y = 0;
    b_Color = 0;

    for(n_File = 0;n_File < 8; n_File ++)
    {
        n_X = 0;

        for(n_Rank = 0;n_Rank < 8; n_Rank ++)
        {

            pdc->Rectangle(n_X,n_Y,n_X+n_FieldHeight,n_Y+n_FieldHeight);
            if(b_Color)
                po_Brush = &o_WhiteBrush;
            else
                po_Brush = &o_BlackBrush;

            pdc->FillRect (CRect(n_X,n_Y,n_X+n_FieldHeight,n_Y
+n_FieldHeight),po_Brush);
            n_X+=n_FieldHeight;
            b_Color = !b_Color;
        }

        n_Y+=n_FieldHeight;
        b_Color = !b_Color;
    }
}

BOOL CchessCtrl::OnEraseBkgnd(CDC* pDC)
{
    // TODO: Add your message handler code here and/or call default

    return FALSE;
    //return COleControl::OnEraseBkgnd(pDC);
}

void CchessCtrl::OnSize(UINT nType, int cx, int cy)
{
    COleControl::OnSize(nType, cx, cy);

    // TODO: Add your message handler code here

    Invalidate(TRUE);

}

i have included the memdc.h in stdafx.h like so:

#pragma once

// stdafx.h : include file for standard system include files,
// or project specific include files that are used frequently,
// but are changed infrequently

#ifndef VC_EXTRALEAN
#define VC_EXTRALEAN // Exclude rarely-used stuff from
Windows headers
#endif

#include "targetver.h"

#define _ATL_CSTRING_EXPLICIT_CONSTRUCTORS // some CString
constructors will be explicit

#include <afxctl.h> // MFC support for ActiveX Controls
#include <afxext.h> // MFC extensions
#ifndef _AFX_NO_OLE_SUPPORT
#include <afxdtctl.h> // MFC support for Internet Explorer 4
Comon Controls
#endif
#ifndef _AFX_NO_AFXCMN_SUPPORT
#include <afxcmn.h> // MFC support for Windows
Common Controls
#endif // _AFX_NO_AFXCMN_SUPPORT

// Delete the two includes below if you do not wish to use the MFC
// database classes
#ifndef _WIN64

#ifndef _AFX_NO_DB_SUPPORT
#include <afxdb.h> // MFC ODBC database classes
#endif // _AFX_NO_DB_SUPPORT

#ifndef _AFX_NO_DAO_SUPPORT
#include <afxdao.h> // MFC DAO database classes
#endif // _AFX_NO_DAO_SUPPORT
#include "memdc.h"

#endif // _WIN64

the CMemDC class:

#ifndef _MEMDC_H_
#define _MEMDC_H_

//////////////////////////////////////////////////
// CMemDC - memory DC
//
// Author: Keith Rule
// Email: keithr@europa.com
// Copyright 1996-2002, Keith Rule
//
// You may freely use or modify this code provided this
// Copyright is included in all derived versions.
//
// History - 10/3/97 Fixed scrolling bug.
// Added print support. - KR
//
// 11/3/99 Fixed most common complaint. Added
// background color fill. - KR
//
// 11/3/99 Added support for mapping modes other than
// MM_TEXT as suggested by Lee Sang Hun. - KR
//
// 02/11/02 Added support for CScrollView as supplied
// by Gary Kirkham. - KR
//
// This class implements a memory Device Context which allows
// flicker free drawing.

class CMemDC : public CDC {
private:
    CBitmap m_bitmap; // Offscreen bitmap
    CBitmap* m_oldBitmap; // bitmap originally found in CMemDC
    CDC* m_pDC; // Saves CDC passed in constructor
    CRect m_rect; // Rectangle of drawing area.
    BOOL m_bMemDC; // TRUE if CDC really is a Memory DC.
public:

    CMemDC(CDC* pDC, const CRect* pRect = NULL) : CDC()
    {
        ASSERT(pDC != NULL);

        // Some initialization
        m_pDC = pDC;
        m_oldBitmap = NULL;
        m_bMemDC = !pDC->IsPrinting();

        // Get the rectangle to draw
        if (pRect == NULL) {
            pDC->GetClipBox(&m_rect);
        } else {
            m_rect = *pRect;
        }

        if (m_bMemDC) {
            // Create a Memory DC
            CreateCompatibleDC(pDC);
            pDC->LPtoDP(&m_rect);

            m_bitmap.CreateCompatibleBitmap(pDC, m_rect.Width(), m_rect.Height
());
            m_oldBitmap = SelectObject(&m_bitmap);

            SetMapMode(pDC->GetMapMode());

            SetWindowExt(pDC->GetWindowExt());
            SetViewportExt(pDC->GetViewportExt());

            pDC->DPtoLP(&m_rect);
            SetWindowOrg(m_rect.left, m_rect.top);
        } else {
            // Make a copy of the relevent parts of the current DC for printing
            m_bPrinting = pDC->m_bPrinting;
            m_hDC = pDC->m_hDC;
            m_hAttribDC = pDC->m_hAttribDC;
        }

        // Fill background
        FillSolidRect(m_rect, pDC->GetBkColor());
    }

    ~CMemDC()
    {
        if (m_bMemDC) {
            // Copy the offscreen bitmap onto the screen.
            m_pDC->BitBlt(m_rect.left, m_rect.top, m_rect.Width(), m_rect.Height
(),
                this, m_rect.left, m_rect.top, SRCCOPY);

            //Swap back the original bitmap.
            SelectObject(m_oldBitmap);
        } else {
            // All we need to do is replace the DC with an illegal value,
            // this keeps us from accidently deleting the handles associated
with
            // the CDC that was passed to the constructor.
            m_hDC = m_hAttribDC = NULL;
        }
    }

    // Allow usage as a pointer
    CMemDC* operator->()
    {
        return this;
    }

    // Allow usage as a pointer
    operator CMemDC*()
    {
        return this;
    }
};

#endif

If i startup my ActiveX test dialog the control flickers a lot when
resized.
It does not work. What have i done wrong, can someone help please?

Thanks.