CListBox::DrawItem

virtual void DrawItem( LPDRAWITEMSTRUCT lpDrawItemStruct );

Parameters

lpDrawItemStruct

A long pointer to a DRAWITEMSTRUCT structure that contains information about the type of drawing required.

Remarks

Called by the framework when a visual aspect of an owner-draw list box changes. The itemAction and itemState members of the DRAWITEMSTRUCT structure define the drawing action that is to be performed.

By default, this member function does nothing. Override this member function to implement drawing for an owner-draw CListBox object. The application should restore all graphics device interface (GDI) objects selected for the display context supplied in lpDrawItemStruct before this member function terminates.

See CWnd::OnDrawItem for a description of the DRAWITEMSTRUCT structure.

Example

// CMyListBox is my owner-drawn list box derived from CListBox. This 
// example draws an item's text centered vertically and horizontally. The 
// list box control was created with the following code:
//   pmyListBox->Create(
//      WS_CHILD|WS_VISIBLE|WS_BORDER|WS_HSCROLL|WS_VSCROLL|
//      LBS_SORT|LBS_MULTIPLESEL|LBS_OWNERDRAWVARIABLE,
//      myRect, pParentWnd, 1);
//
void CMyListBox::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct) 
{
   ASSERT(lpDrawItemStruct->CtlType == ODT_LISTBOX);
   LPCTSTR lpszText = (LPCTSTR) lpDrawItemStruct->itemData;
   ASSERT(lpszText != NULL);
   CDC dc;

   dc.Attach(lpDrawItemStruct->hDC);

   // Save these value to restore them when done drawing.
   COLORREF crOldTextColor = dc.GetTextColor();
   COLORREF crOldBkColor = dc.GetBkColor();

   // If this item is selected, set the background color 
   // and the text color to appropriate values. Also, erase
   // rect by filling it with the background color.
   if ((lpDrawItemStruct->itemAction | ODA_SELECT) &&
      (lpDrawItemStruct->itemState & ODS_SELECTED))
   {
      dc.SetTextColor(::GetSysColor(COLOR_HIGHLIGHTTEXT));
      dc.SetBkColor(::GetSysColor(COLOR_HIGHLIGHT));
      dc.FillSolidRect(&lpDrawItemStruct->rcItem, 
         ::GetSysColor(COLOR_HIGHLIGHT));
   }
   else
      dc.FillSolidRect(&lpDrawItemStruct->rcItem, crOldBkColor);

   // If this item has the focus, draw a red frame around the
   // item's rect.
   if ((lpDrawItemStruct->itemAction | ODA_FOCUS) &&
      (lpDrawItemStruct->itemState & ODS_FOCUS))
   {
      CBrush br(RGB(255, 0, 0));
      dc.FrameRect(&lpDrawItemStruct->rcItem, &br);
   }

   // Draw the text.
   dc.DrawText(
      lpszText,
      strlen(lpszText),
      &lpDrawItemStruct->rcItem,
      DT_CENTER|DT_SINGLELINE|DT_VCENTER);

   // Reset the background color and the text color back to their
   // original values.
   dc.SetTextColor(crOldTextColor);
   dc.SetBkColor(crOldBkColor);

   dc.Detach();
}

CListBox Overview | Class Members | Hierarchy Chart