This property returns the index of the subitem associated with a ColumnHeader object in a ListView control.
object.SubItemIndex [= integer]
Subitems are arrays of strings representing the ListItem object's data when displayed in Report view.
The first column header always has a SubItemIndex property set to 0 because the small icon and the ListItem object's text always appear in the first column and are considered ListItem objects rather than subitems.
The number of column headers dictates the number of subitems. There is always exactly one more column header than there are subitems.