Using Radzen you can create master/detail with two grids in three easy steps:

  1. Drop DataGrid component to Radzen design surface, bind it to your first table (in my case Orders from Northwind OData service) and auto-generate columns master-detail-two-grids1.png Bind first DataGrid to Orders

  2. Define select event for the DataGrid component to invoke Order Details with filter OrderID eq ${event.OrderID} and set a property orderDetails to the result value master-detail-two-grids2.png Invoke Order Details and set property value

  3. Drop second DataGrid component to Radzen design surface, bind it to orderDetails property and auto-generate columns master-detail-two-grids3.png Bind second DataGrid to Order Details

  4. Run the application to check Order details for the selected Order master-detail-two-grids4.png Order Details for selected Order

Enjoy!