Get the index of a focused list item

[ssimop]

Supposed that an item in a SysListView32 list, for example a line of windows explorer, is focused, for example with a a.Select(SELFLAG_TAKESELECTION) statement. Is there a way, for example with a SendMessage command, to get the index of this list item. I understand that it can be done with a loop of GetListViewItemText statements but if the list is long it takes considerable time ! Any advice is welcome. Thanks in advance.