WM_MEASUREITEM (in List Boxes) - Syntax

This notification is sent to the owner of a list box control to establish the height and width for an item in that control.

param1
     SHORT  sListBox    /*  List-box identifier. */

param2
     SHORT  sItemIndex  /*  Item index. */

returns
     SHORT  sHeight     /*  Height of item. */
     SHORT  sWidth      /*  Width of item. */