I've been successful loading a datatable in a asp.net core project, But the page doesn't show the grid in the Resource view as in the attachment below. You can right click the page and view the source code containing the loaded data, it just doesn't show.
Did I miss something?
I'm afraid that the sample you gave us won't be built in my environment.
Because of this, I created a new ASP.NET Core application, put an igGrid in a view and reused your codes which seem to be used to initialize the igGrid. Nevertheless, I couldn't reproduce your issue.
I attached a sample application I gave a try. Could you run it and see if it works fine in your environment? In my environment, it shows igGrid expectedly.
As I couldn't reproduce the issue on my side, this is just my guess, but there might be some errors written in the console of browser's developer tool. If there are some, those error messages might be helpful to debug your application.