property Items.ItemToIndex (Item as HITEM) as Long
Retrieves the index of item into Items collection given its handle.

TypeDescription
Item as HITEM A long expression that indicates the item's handle.
Long A long expression that indicates the index of the item in Items collection. 

Use the ItemToIndex property to get the item's index into Items collection.  Use ItemPosition property to change the item's position. Use the ItemByIndex property to get an item giving its index.