When the GridView.Sorting event is raised, you can use the GridViewSortEventArgs.SortDirection property to determine the order in which the System.Web.UI.WebControls.GridView control will sort its items (based on the sort expression) when the sort operation is performed. Because the GridView.Sorting event occurs before the sort operation, you can also use the GridViewSortEventArgs.SortDirection property to programmatically set the sort direction.