Thank you for contacting us.
The most suitable solution in your scenario is to use the SortChanging event and change the Direction only when it is Ascending:
SortDescriptor = TryCast(e.NewItems(0), SortDescriptor)
sortDescriptor.Direction = ListSortDirection.Ascending
sortDescriptor.Direction = ListSortDirection.Descending
I hope you find this useful. Let me know if you have further questions.
the Telerik team
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