An application sends an LB_GETITEMRECT message to retrieve the dimensions of the rectangle that bounds a list box item as it is currently displayed in the list box.
LB_GETITEMRECT wParam = (WPARAM) index; // item index lParam = (LPARAM) (RECT FAR*) lprc; // address of rectangle
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.
If an error occurs, the return value is LB_ERR.