Shape.Index Property (Visio)
Gets the ordinal position of a Shape object in the Shapes collection. Read-only.
Most collections are indexed starting with 1 rather than zero (0), so the index of the first element is 1, the index of the second element is 2, and so forth. The index of the last element in a collection is the same as the value of that collection's Count property. You can iterate through a collection by using these index values. Adding objects to or deleting objects from a collection can change the index values of other objects in the collection.