Returns the index number of the specified slide within the Slides collection. Read-only Long.
Remarks
Unlike the SlideID property, the SlideIndex property of a Slide object can change when you add slides to the presentation or rearrange the slides in the presentation. Therefore, using the FindBySlideID method with the slide's ID number can be a more reliable way to return a specific Slide object from a Slides collection than using the Item method with the slide's index number.