Because the DetailsView.PageIndexChanging event occurs before the System.Web.UI.WebControls.DetailsView control performs the paging operation, the DetailsView.PageIndex property of the control contains the index of the previously displayed page and cannot be used to determine the index of the page selected by the user. Use the DetailsViewPageEventArgs.NewPageIndex property to determine the page index. You can also use this property to programmatically override the page index selected by the user by setting it to another value.