HDN_ITEMCHANGING notification code

Notifies a header control's parent window that the attributes of a header item are about to change. This notification code is sent in the form of a WM_NOTIFY message.

HDN_ITEMCHANGING

    pNMHeader = (LPNMHEADER) lParam; 

Parameters

lParam

A pointer to an NMHEADER structure that contains information about the header control and the header item, including the attributes that are about to change.

Return value

Returns FALSE to allow the changes, or TRUE to prevent them.

Requirements