WM_COMPAREITEM

Overview

Group

Quick Info

Windows NT
Yes
Win95
Yes
Win32s
Yes
Import Library
-
Header File
winuser.h
Unicode
No
Platform Notes
None

Windows sends the WM_COMPAREITEM message to determine the relative position of a new item in the sorted list of an owner-drawn combo box or list box. Whenever the application adds a new item, Windows sends this message to the owner of a combo box or list box created with the CBS_SORT or LBS_SORT style.

WM_COMPAREITEM

idCtl = wParam; // control identifier

lpcis = (LPCOMPAREITEMSTRUCT) lParam; // structure with items

Parameters
idCtl

Value of wParam. Specifies the identifier of the control that sent the WM_COMPAREITEM message.

lpcis

Value of lParam. Points to a COMPAREITEMSTRUCT structure that contains the identifiers and application-supplied data for two items in the combo or list box.

Return Values
The return value indicates the relative position of the two items. It may be any of the following:

Value	Meaning
1	Item 1 precedes item 2 in the sorted order.
0	Items 1 and 2 are equivalent in the sorted order.
1	Item 1 follows item 2 in the sorted order.

Remarks
When the owner of an owner-drawn combo box or list box receives this message, the owner returns a value indicating which of the items specified by the COMPAREITEMSTRUCT structure will appear before the other. Typically, Windows sends this message several times until it determines the exact position for the new item.