BEST TECHNIQUES - How do you modify a MVC layoutpage

Hi guys
Can someone advise what are the best techniques for controlling an MVC Core2 _LayoutPage ?

I want to be able to pass model data (from the database) 

1. Initially I used BaseControllers, but it seems the ViewBag data does not work in MVC Core 2.

2. I tried passing a partial View and accessing it with Jquery, but that would be too cumbersome for a site with lots of pages.

Here is my current project

    public class HomeController : MyBaseController /// STEP 1 - inherit custom controller
    {

  public class MyBaseController : Controller  /// STEP 2 - Create custom controller
    {
        public   MyBaseController()
        {
            ViewData["m"] =  "test";
        }
    }
}


@{                                             // STEP 3 - Add directive to my layout page 

    var Ehi = ViewData["m"];
}


@Ehi // STEP 4 - Insert the variable into my layout page