Re: CListBox::DrawItem(), CListBox::AddItem(), CListBox::SetItemData()

From:
"David Ching" <dc@remove-this.dcsoft.com>
Newsgroups:
microsoft.public.vc.mfc
Date:
Wed, 7 Nov 2007 22:06:19 -0800
Message-ID:
<YHxYi.6103$ww2.2595@newssvr19.news.prodigy.net>
"William" <port@mx15.freecom.ne.jp> wrote in message
news:usFhxocIIHA.3768@TK2MSFTNGP06.phx.gbl...

Env: WindowsXP, VC++6.00

To have individual lines inside a CListBox to be different colors, I used
Dr. GUI's solution in [MSDN] which can be refered at "Ask Dr. GUI #43".
In the solution, the color of a line is specified by SetItemData() as
follows,

int CMyListBox::AddItem(const CString& str, COLORREF rgbText)
{
int nIndex;
nIndex = AddString(str);
if( CB_ERR != nIndex )
   SetItemData(nIndex, rgbText);
return nIndex;
}

And the line is drawed by the color at the following function.
void CMyListBox::DrawItem(LPDRAWITEMSTRUCT lpDIS)
{
CDC dc;
CRect rcItem(lpDIS->rcItem);
UINT nIndex = lpDIS->itemID;
COLORREF rgbBkgnd = ::GetSysColor((lpDIS->itemState & ODS_SELECTED) ?
COLOR_HIGHLIGHT : COLOR_WINDOW);
dc.Attach(lpDIS->hDC);
CBrush br(rgbBkgnd);
dc.FillRect(rcItem, &br);

if( lpDIS->itemState & ODS_FOCUS )
 dc.DrawFocusRect(rcItem);

if( nIndex != (UINT)-1 )
{
 // The text color is stored as the item data.
 COLORREF rgbText = (lpDIS->itemState & ODS_SELECTED) ?
::GetSysColor(COLOR_HIGHLIGHTTEXT) : GetItemData(nIndex);
 CString str;
 GetText(nIndex, str);
 dc.SetBkColor(rgbBkgnd);
 dc.SetTextColor(rgbText);
 dc.TextOut(rcItem.left + 2, rcItem.top + 2, str);
}
dc.Detach();
}

Obviously, the line's ItemData is used. I am tring to use line's ItemData
for other purpose. Then, how should I fix the above functions so that
ItemData is not occupied.

TIA
William


Have the list's ItemData point to a struct such as:

struct ListItemData
{
    COLORREF m_rgbText; // color of this item's text
    void *m_pOther; // your "other purpose"
};

that way the ItemData can contain both the color and your data.

-- David

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