Hi Ben,
Yes, you can update a data item of a grid by using its data source. For example (JavaScript):
// get a reference to the grid
var grid = $("#grid").data("kendoGrid")l
// get its data source
var dataSource = grid.dataSource();
// get some data item
var firstDataItem = dataSource.at(0);
// update a property of the data item
firstDataItem.set("FirstName", "New Value");
// sync the changes with the server-side
dataSource.sync();
You can execute this code in the OnRequestEnd of the child grid.
If the formula is calculated at the server side you should also initiate a read() operation of the parent grid so it gets the latest data:
dataSource.read();
Regards,
Atanas Korchev
Telerik