CListBox::MeasureItem
Visual Studio 2012
Called by the framework when a list box with an owner-draw style is created.
virtual void MeasureItem( LPMEASUREITEMSTRUCT lpMeasureItemStruct );
By default, this member function does nothing. Override this member function and fill in the MEASUREITEMSTRUCT structure to inform Windows of the list-box dimensions. If the list box is created with the LBS_OWNERDRAWVARIABLE style, the framework calls this member function for each item in the list box. Otherwise, this member is called only once.
For further information about using the LBS_OWNERDRAWFIXED style in an owner-draw list box created with the SubclassDlgItem member function of CWnd, see the discussion in Technical Note 14.
See CWnd::OnMeasureItem for a description of the MEASUREITEMSTRUCT structure.
// CMyODListBox is my owner-drawn list box derived from CListBox. This // example measures an item and sets the height of the item to twice the // vertical extent of its text. The list box control was created with the // following code: // m_myODListBox.Create( // WS_CHILD|WS_VISIBLE|WS_BORDER|WS_HSCROLL|WS_VSCROLL| // LBS_SORT|LBS_MULTIPLESEL|LBS_OWNERDRAWVARIABLE|LBS_WANTKEYBOARDINPUT, // CRect(10,250,200,450), pParentWnd, IDC_MYODLISTBOX); // void CMyODListBox::MeasureItem(LPMEASUREITEMSTRUCT lpMeasureItemStruct) { ASSERT(lpMeasureItemStruct->CtlType == ODT_LISTBOX); LPCTSTR lpszText = (LPCTSTR) lpMeasureItemStruct->itemData; ASSERT(lpszText != NULL); CSize sz; CDC* pDC = GetDC(); sz = pDC->GetTextExtent(lpszText); ReleaseDC(pDC); lpMeasureItemStruct->itemHeight = 2*sz.cy; }
