Query.cs

using GraphQLSampleApp.DataAccess.DAO;
using GraphQLSampleApp.DataAccess.Entity;
using HotChocolate;
using HotChocolate.Subscriptions;
using System.Collections.Generic;
using System.Threading.Tasks;

namespace GraphQLSampleApp.DataAccess
{
    public class Query
    {
        public List<Employee> AllEmployeeOnly([Service] EmployeeRepository employeeRepository) =>
            employeeRepository.GetEmployees();

        public List<Employee> AllEmployeeWithDepartment([Service] EmployeeRepository employeeRepository) =>
            employeeRepository.GetEmployeesWithDepartment();

        public async Task<Employee> GetEmployeeById([Service] EmployeeRepository employeeRepository, 
            [Service]ITopicEventSender eventSender, int id)
        {
            Employee gottenEmployee = employeeRepository.GetEmployeeById(id);
            await eventSender.SendAsync("ReturnedEmployee", gottenEmployee);
            return gottenEmployee;
        }           

        public List<Department> AllDepartmentsOnly([Service] DepartmentRepository departmentRepository) =>
            departmentRepository.GetAllDepartmentOnly();

        public List<Department> AllDepartmentsWithEmployee([Service] DepartmentRepository departmentRepository) =>
            departmentRepository.GetAllDepartmentsWithEmployee();
    }
}