Demonstrates how to route works with abstract base controllers actions and inherited controllers in ASP.NET Core WebAPI

ValuesController.cs

// Example for question https://stackoverflow.com/questions/53488184/asp-net-core-controllers-route-attribute-inheritance-and-abstract-controllers-ac#53488184

public abstract class BaseApiController : Controller
    {
        [HttpGet]
        [Route("")]
        public virtual IActionResult GetAll()
        {
            return Ok("GetAll action from base");
        }

        [HttpGet]
        [Route("{id}")]
        public virtual IActionResult GetById(int id)
        {
            return Ok($"GetById action from base with id: {id}");
        }

        [HttpPost]
        [Route("")]
        public virtual IActionResult Insert(string model)
        {
            return Ok("Insert action from base");
        }
    }

    [Route("api/Student")]
    public class StudentController : BaseApiController
    {
        [HttpGet]
        [Route("{id}/ShowNotes")]
        public virtual IActionResult ShowNotes(int id)
        {
            return Ok($"ShowNotes action from Student with id {id}");
        }
    }   

    [Route("api/Teacher")]
    public class TeacherController : BaseApiController
    {
        [HttpGet]
        [Route("{id}/ShowHours")]
        public virtual IActionResult ShowHours(int id)
        {
            return Ok($"ShowHours action from Teacher with id {id}");
        }
    }

The result:

GET http://localhost:51087/api/Student
GetAll action from base
GET http://localhost:51087/api/Student/1
GetById action from base with id: 1
GET http://localhost:51087/api/Student/1/ShowNotes
ShowNotes action from Student with id 1
GET http://localhost:51087/api/Teacher
GetAll action from base
GET http://localhost:51087/api/Teacher/2
GetById action from base with id: 2
GET http://localhost:51087/api/Teacher/2/ShowHours
ShowHours action from Teacher with id 2