I want to implement the following:
so, Kendo UI Grid and inside each row it has a panelbar. I try to find a solution, but most cases are vice versa: add a grid to panelbar. As I understand, I just need to add a child row to every row of grid. How to implement it?
I use ASP.NET Core.

You can do it with the
Detail Template of Grid.Here is the sample : Dojo Sample
Check the reference here : Detail template