CComboBox::DrawItem
Called by the framework when a visual aspect of an owner-draw combo box changes.
virtual void DrawItem(
LPDRAWITEMSTRUCT lpDrawItemStruct
);
Parameters
- lpDrawItemStruct
A pointer to a DRAWITEMSTRUCT structure that contains information about the type of drawing required.
Remarks
The itemAction member of the DRAWITEMSTRUCT structure defines the drawing action that is to be performed. See CWnd::OnDrawItem for a description of this structure.
By default, this member function does nothing. Override this member function to implement drawing for an owner-draw CComboBox object. Before this member function terminates, the application should restore all graphics device interface (GDI) objects selected for the display context supplied in lpDrawItemStruct.
Example
// CMyComboBox is my owner-drawn combo box derived from CComboBox. This
// example draws an item's text centered vertically and horizontally. The
// combo box control was created with the following code:
// pmyComboBox->Create(
// WS_CHILD|WS_VISIBLE|WS_BORDER|WS_HSCROLL|WS_VSCROLL|
// CBS_SORT|CBS_OWNERDRAWVARIABLE,
// myRect, pParentWnd, 1);
//
void CMyComboBox::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct)
{
ASSERT(lpDrawItemStruct->CtlType == ODT_COMBOBOX);
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. Erase
// the 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);
}
// Draw the text.
dc.DrawText(
lpszText,
(int)_tcslen(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();
}
Requirements
Header: afxwin.h