CComboBox::CompareItem
Called by the framework to determine the relative position of a new item in the list-box portion of a sorted owner-draw combo box.
virtual int CompareItem(
LPCOMPAREITEMSTRUCT lpCompareItemStruct
);
Parameters
- lpCompareItemStruct
A long pointer to a COMPAREITEMSTRUCT structure.
Return Value
Indicates the relative position of the two items described in the COMPAREITEMSTRUCT structure. It can be any of the following values:
Value |
Meaning |
|---|---|
– 1 |
Item 1 sorts before item 2. |
0 |
Item 1 and item 2 sort the same. |
1 |
Item 1 sorts after item 2. |
See CWnd::OnCompareItem for a description of COMPAREITEMSTRUCT.
Remarks
By default, this member function does nothing. If you create an owner-draw combo box with the LBS_SORT style, you must override this member function to assist the framework in sorting new items added to the list box.
Example
// CMyComboBox is my owner-drawn combo box derived from CComboBox. This
// example compares two items using strcmp to sort items in reverse
// alphabetical order. 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);
//
int CMyComboBox::CompareItem(LPCOMPAREITEMSTRUCT lpCompareItemStruct)
{
int iComp = 0;
ASSERT(lpCompareItemStruct->CtlType == ODT_COMBOBOX);
LPCTSTR lpszText1 = (LPCTSTR) lpCompareItemStruct->itemData1;
ASSERT(lpszText1 != NULL);
LPCTSTR lpszText2 = (LPCTSTR) lpCompareItemStruct->itemData2;
ASSERT(lpszText2 != NULL);
if (NULL != lpszText1 && NULL != lpszText2)
{
iComp = _tcscmp(lpszText2, lpszText1);
}
return iComp;
}
Requirements
Header: afxwin.h