An application sends an LB_GETITEMHEIGHT message to retrieve the height of items in a list box.
LB_GETITEMHEIGHT wParam = (WPARAM) index; // item index lParam = 0; // not used; must be zero
Windows 95: The wParam parameter is limited to 16-bit values. This means list boxes cannot contain more than 32,767 items. Although the number of items is restricted, the total size in bytes of the items in a listbox is limited only by available memory.
The return value is the height, in pixels, of each item in the list box. The return value is the height of the item specified by the index parameter if the list box has the LBS_OWNERDRAWVARIABLE style. The return value is LB_ERR if an error occurs.