CComboBox::DrawItem
呼叫框架,其在主控描繪下拉式方塊的視覺外觀變更。
virtual void DrawItem(
LPDRAWITEMSTRUCT lpDrawItemStruct
);
參數
- lpDrawItemStruct
out 包含針對需要的繪圖的資訊的 DRAWITEMSTRUCT 結構的指標。
備註
DRAWITEMSTRUCT 結構的 itemAction 成員定義要執行的繪圖動作。 為這個結構描述的參閱 CWnd::OnDrawItem 。
根據預設,此成員函式不會執行任何動作。 覆寫這個成員函式實作主控描繪 CComboBox 物件的繪圖。 在此成員函式結束之前,應用程式應該還原為顯示內容選取的所有圖形裝置介面 (GDI) 物件提供在 lpDrawItemStruct。
範例
// 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();
}
需求
Header: afxwin.h