NM_GETCUSTOMSPLITRECT notification code

Sent by a button control to its parent to get measurements for the two rectangles of the split button. This notification code is sent in the form of a WM_NOTIFY message.

NM_GETCUSTOMSPLITRECT
        
    nmCustomSplit = (NMCUSTOMSPLITRECTINFO *) lParam;

Parameters

lParam

A pointer to an NMCUSTOMSPLITRECTINFO to receive bounding rectangles information. The NMCUSTOMSPLITRECTINFO structure is sent with the notification code as a request for the parent to provide measurements for the rectangles of the split button.

Return value

Return CDRF_SKIPDEFAULT to tell the button control to use the values returned in the NMCUSTOMSPLITRECTINFO structure; otherwise, return CDRF_DODEFAULT.

Remarks

This notification code is sent by a button control before it is drawn. The button must be of style BS_SPLITBUTTON or BS_DEFSPLITBUTTON. If the rectangles returned to the control in lParam are not valid, they are ignored.

Requirements