When you sort multiple columns, the same sorting options are applied to each column, starting from the leftmost column in the range and proceeding to the right.
To sort multiple columns using a different sorting order for each, you can either call the Sort(SortFlags,Int32) method multiple times or set each column's Column.Sort property and call the Sort(SortFlags,Int32) method including the SortFlags.UseColSort flag in the flags parameter.