CListBox::MeasureItem
Called by the framework when a list box with an owner-draw style is created.
virtual void MeasureItem(
LPMEASUREITEMSTRUCT lpMeasureItemStruct
);
Parameters
- lpMeasureItemStruct
A long pointer to a MEASUREITEMSTRUCT structure.
Remarks
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**.**
Example
// 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;
}
Requirements
Header: afxwin.h