According to the documentation DataView.Sort is a string that contains the column name followed by "ASC" (ascending) or "DESC" (descending). Columns are sorted ascending by default. Multiple columns can be separated by commas.
If you pass long name: Descending or Ascending (from System.Web.UI.WebControls.SortDirection enum)
the error is reported:
System.IndexOutOfRangeException: Cannot find column LastName Descending. at System.Data.DataTable.ParseSortString(String sortString) at System.Data.DataView.UpdateIndex(Boolean force, Boolean fireEvent) at System.Data.DataView.UpdateIndex(Boolean force) at System.Data.DataView.SetIndex2(String newSort, DataViewRowState newRowStates, DataExpression newRowFilter, Boolean fireEvent) at System.Data.DataView.SetIndex(String newSort, DataViewRowState newRowStates, DataExpression newRowFilter) at System.Data.DataView..ctor(DataTable table, String RowFilter, String Sort, DataViewRowState RowState)