RadSlideView provides the following events.
SlidingToIndex: The event occurs when the current selection is changing (executing a slide). Its event arguments are of type SlideViewSlidingToIndexEventArgs and expose the new index and a cancelation option via the Index and Cancel properties. Setting the Cancel property of the event arguments to True will stop the sliding action.
SlidedToIndex: The event occurs when the current selection is changed (a slide is executed). Its event arguments are of type SlideViewSlidedToIndexEventArgs and expose the new index via the Index property.