Problem in resizing with scroll bar

From:

Mohit <behappy.mohit@gmail.com>

Newsgroups:

microsoft.public.vc.mfc

Date:

Tue, 23 Jun 2009 10:19:38 -0700 (PDT)

Message-ID:

<dbd1a2f2-0129-444c-bb4e-e1d228f71adf@y10g2000prc.googlegroups.com>

Hi,
I m making dialog based application .I am trying to make resizable
dialog with scroll bar.I had put maximum and minimum size in
void CMainDlg::OnGetMinMaxInfo(MINMAXINFO* lpMMI)
{
                lpMMI->ptMinTrackSize.x=710;
lpMMI->ptMinTrackSize.y=335;

lpMMI->ptMaxTrackSize.x =710;
        lpMMI->ptMaxTrackSize.y =675;

        CDialog::OnGetMinMaxInfo(lpMMI);
}

Vertical scroll coding
void CMainDlg::OnVScroll(UINT nSBCode, UINT nPos, CScrollBar*
pScrollBar)
{
        int nDelta;
        int nMaxPos = m_rect.Height() - m_nCurHeight;

        {switch (nSBCode)
        {
        case SB_LINEDOWN:
                if (m_nScrollPos >= nMaxPos)
                        return;
                nDelta = min(nMaxPos/100,nMaxPos-m_nScrollPos);
                break;

        case SB_LINEUP:
                if (m_nScrollPos <= 0)
                        return;
                nDelta = -min(nMaxPos/100,m_nScrollPos);
                break;

         case SB_PAGEDOWN:
                if (m_nScrollPos >= nMaxPos)
                        return;
                nDelta = min(nMaxPos/10,nMaxPos-m_nScrollPos);
                break;

        case SB_THUMBPOSITION:
                nDelta = (int)nPos - m_nScrollPos;
                break;

        case SB_PAGEUP:
                if (m_nScrollPos <= 0)
                        return;
                nDelta = -min(nMaxPos/10,m_nScrollPos);
                break;

         default:
                return;
        }
        m_nScrollPos += nDelta;
        SetScrollPos(SB_VERT,m_nScrollPos,TRUE);
        ScrollWindow(0,-nDelta);
        }
        CDialog::OnVScroll(nSBCode, nPos, pScrollBar);

}

void CMainDlg::OnSize(UINT nType, int cx, int cy)
{
    if(nType == SIZE_MINIMIZED)
    {
        ShowWindow(SW_HIDE);
    }
    else
    {CDialog::OnSize(nType, cx, cy);
                    m_nCurHeight = cy;
        m_nCurWidth = cx;
    int nScrollMax;
    int nScrollMaxhori;

    if (cy < m_rect.Height())//For vertical scorll barr
    {
         nScrollMax = m_rect.Height() - cy;
nScrollMax =nScrollMax-30;
    }
    else
         nScrollMax = 0;

    if (cy < m_rect.Width())
    {
         nScrollMaxhori = m_rect.Height() - cy;
    }
    else
         nScrollMaxhori = 0;

    SCROLLINFO si;
    si.cbSize = sizeof(SCROLLINFO);
    si.fMask = SIF_ALL; // SIF_ALL = SIF_PAGE | SIF_RANGE | SIF_POS;
    si.nMin = 0;
    si.nMax = nScrollMax;
    si.nPage = si.nMax/10;
    si.nPos = 0;
        SetScrollInfo(SB_VERT, &si, TRUE);
SetScrollPos(SB_VERT,m_nScrollPos,TRUE);

    }
}

My maximum size is default dialog size
My problem is when i decrease size of dialog and scroll down then
increase size vertically
Then some extra dialog start appearing which i dont want.
Can any body suggest me how can i solve my problem

Mohit