How to retrieve data from the database using ASP.NET MVC - asp.net

Question

I have two models/tables, one is User and the other is role the relationship is one Role can have many users. I am trying to loop through the data in the user model navigation property but i am getting an error that its returning null.
User model
public class User
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int User_Id { get; set; }
[Required]
[Display(Name ="User Name")]
public string User_Name { get; set; }
[Required(ErrorMessage = "The Field Is Required")]
[MaxLength(10, ErrorMessage = " Please Enter A Valid Input")]
public string Password { get; set; }
//Nav
[ForeignKey("RoleId")]
[Display(Name ="User Role:")]
public int RoleId { get; set;}
public Role Role { get; set; }
}
Role Model
public class Role
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Role_id { get; set; }
[Required(ErrorMessage ="This field is required")]
[Display(Name ="Role Name :")]
public string RoleType { get; set; }
//nav
public List<User> Users { get; set; }
}
Controller action Method:
public async Task<IActionResult> Index()
{
var viewModel = await userRepository.GetAllUsersAlongWithRolesAsync();
//var viewModel = await baseRepository.GetAllObjectsAsync();
return View("Index",viewModel);
}
Updates: UserRepository that inherited from the IBaseRepository
public class UserRepository : BaseRepository<User>, IUserRepository
{
private readonly ApplicationDbContext _Context;
public UserRepository(ApplicationDbContext context):base (context)
{
_Context = context;
}
public async Task <IEnumerable<User>> GetAllUsersAlongWithRolesAsync()
{
var getUsers = await _Context.Users.Include(u => u.Role).ToListAsync();
return getUsers;
}
}
In the User controller for injecting:
// injection
private readonly IBaseRepository<User> baseRepository;
private readonly IBaseRepository<Role> roleRepository;
private readonly IUserRepository userRepository;
public UserController(IBaseRepository<User> _baseRepository, IBaseRepository<Role> _roleRepository, IUserRepository userRepository)
{
baseRepository = _baseRepository;
this.roleRepository = _roleRepository;
this.userRepository = userRepository;
}

Answer 1

Since your method GetAllObjectsAsync is so generic, you probably won't be able to add the .Include() you need.
I'd suggest a separate method GetAllUsers() to your repository - possibly the concrete UserRepository, if you have that:
public async Task<IEnumerable<User>> GetAllUsersAsync()
{
var getUsers = await _Context.Users.Include(u => u.Role).ToListAsync();
return getUsers;
}