I would like to have an event equivalent to the OnRead for the Grid so that I could make custom data operations such as applying custom filtering to the root items. 

---

ADMIN EDIT

In the meantime, loading data on demand only when a node expands can make database queries happen less often and return less data: https://docs.telerik.com/blazor-ui/components/treelist/data-binding/load-on-demand

---