listcontrol: EnsureVisible() flickering

From:

mfc <mfcprog@googlemail.com>

Newsgroups:

microsoft.public.vc.mfc

Date:

Wed, 24 Nov 2010 02:28:54 -0800 (PST)

Message-ID:

<276291a8-1afd-4d3a-b357-b959fb0f29fa@w14g2000yqe.googlegroups.com>

Hi,

I`ve installed a listcontrol item (report style) on a popup dialog.
I`ve created my own headercontrol and I use no scrollbars.

//called from the OnInitDialog() method of the dialog where the
listcontrol will be shown
void ImageListCtrl::Init(void)
{
    //another way to hide scrollbars
    InitializeFlatSB(this->m_hWnd);
    FlatSB_EnableScrollBar(this->m_hWnd, SB_BOTH, ESB_DISABLE_BOTH);
}

Instead of using the scrollbars I want to use two buttons to scroll.
The size of the list can contain always 10 items.

Now if I click on the button to visit the next 10 items of the list, I
will always get some flickers. I`ve tried to use both methods Scroll()
and EnsureVisible() with no success.

The member of my listcontrol class is: ImageListCtrl m_ListNodes

//OnButtonClick() handler:
void CStatePage::OnBnClickedNlistNext()
{
    UINT nbrOfItems = m_ListNodes.GetItemCount();

                //get height of one item to now the scroll-size
                CRect itemrect;
    m_ListNodes.GetItemRect(0,&itemrect, LVIR_BOUNDS);
    UINT height = itemrect.Height();

               int top = m_ListNodes.GetTopIndex();
               int newFirstItem=0;

               if(top < (nbrOfItems -10))
                      newFirstItem = top+10;

               else
                      newFirstItem = nbrOfItems - nbrOfItems %10;

                  m_ListNodes.EnsureVisible(newFirstItem , FALSE);
}

In my listcontrol class, I only use the OnPaint() handler:

void ImageListCtrl::OnPaint()
{
    CPaintDC dc(this);

    CRect rect;
    GetClientRect(&rect);
    CMemDC memDC(&dc, rect);

    //funky code to allow use to double buffer
    //the onpaint calls for flicker free drawing
    //of the list items

    CRect headerRect;
    GetDlgItem(0)->GetWindowRect(&headerRect);
    ScreenToClient(&headerRect);
    dc.ExcludeClipRect(&headerRect);

    CRect clip;
    memDC.GetClipBox(&clip);
    memDC.FillSolidRect(clip, RGB(0,0,25));

    SetTextBkColor(RGB(0,0,25));
    SetTextColor(RGB(255,255,255));

    DefWindowProc(WM_PAINT, (WPARAM)memDC->m_hDC, (LPARAM)0);
}

best regards
Hans