To load data from multiple level I use include then after I update my project to dotnet core 3.1 it's not working and fourth level always null
var oldMethod = _depositRepository.All()
.Include(n => n.StudentStatus.Student.Person.Gender)
and I try using ThenInclude
var newMethod = _depositRepository.All()
.Include(n => n.StudentStatus)
.ThenInclude(s => s.Student)
.ThenInclude(p => p.Person)
.ThenInclude(g => g.Gender)
In both method the Gender
always be null
public IQueryable<T> All()
{
return DbSet.AsNoTracking().AsQueryable();
}
I follow this tutorial Loading Related Data
Edit 1: some of my code
public class IEntity<IId>
{
public IId Id { get; set; }
public string Name { get; set; }
}
public class Gender : IEntity<byte>
{
}
public class Person: IEntity<int>
{
public byte GenderId { get; set; }
public virtual Gender Gender { get; set; }
}
public class Student : IEntity<int>
{
public int PersonId { get; set; }
public virtual Person Person { get; set; }
}
public class StudentStatus : IEntity<int>
{
public int StudentId { get; set; }
public virtual Student Student { get; set; }
}
public class Deposit : IEntity<int>
{
public int StudentStatusId { get; set; }
public StudentStatus StudentStatus { get; set; }
}
public interface IRepository<T, IId>
where T : IEntity<IId>
{
IQueryable<T> All();
}
public class EfRepository<T, IId> : IRepository<T, IId>
where T : IEntity<IId>
{
private readonly UniversityDbContext _dbContext;
public EfRepository(UniversityDbContext dbContext)
{
_dbContext = dbContext;
}
private DbSet<T> DbSet => _dbContext.Set<T>();
public IQueryable<T> All()
{
return DbSet.AsNoTracking().AsQueryable();
}
public class FinancialController : Controller
{
private readonly IRepository<Deposit, int> _depositRepository;
public FinancialController(IRepository<Deposit, int>)
{
_depositRepository = depositRepository;
}
public IActionResult GetStatistic()
{
var model= _depositRepository.All()
.Include(n => n.StudentStatus)
.ThenInclude(s => s.Student)
.ThenInclude(p => p.Person)
.ThenInclude(g => g.Gender).ToList();
return Json(model);
}
}
I conclude that there is a restriction on how deep you can go with ThenInclude
which is three level. So I work around it by calling _genderRepository
and pass GenderId
to get Gender
object however I don't think this is the best solution but it's easier than write sql
code.
var newMethod = _depositRepository.All()
.Include(n => n.StudentStatus)
.ThenInclude(s => s.Student)
.ThenInclude(p => p.Person)
.ThenInclude(g => g.Gender)
.Select(n=>new {
...
Gender=_genderRepository.Find(k=>k.Id==n.StudentStatus.Student.Person.GenderId)
}
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