Returning Entity with its children - entity-framework

Question

Hi I am trying to return all vehicles with their recorded mileage through an api using ASP.Net Core with the following code:
// GET: api/values
[HttpGet]
public IEnumerable<Vehicle> Get()
{
return _context.Vehicles.Include(m=>m.Mileages).ToList();
}
However this only returns the first vehicle with its mileages and not the others (there are five dummy vehicles in the db all with an initial mileage).
If I change the code to:
// GET: api/values
[HttpGet]
public IEnumerable<Vehicle> Get()
{
return _context.Vehicles.ToList();
}
it returns the full list of vehicles but no mileage.
My class files are:
public class Vehicle
{
public Vehicle()
{
Mileages = new List<Mileage>();
}
public int Id { get; set; }
public string Registration { get; set; }
public string Make { get; set; }
public string Model { get; set; }
public Marked Marked { get; set; }
public ICollection<Mileage> Mileages { get; set; }
}
and
public class Mileage
{
public int Id { get; set; }
public DateTime MileageDate { get; set; }
public string RecordedMileage { get; set; }
//Navigation Properties
public int VehicleId { get; set; }
public Vehicle Vehicle { get; set; }
}
thanks for looking!
Tuppers

Answer 1

you can have them auto-load (lazy loading) using proxies... but for that, your foreign entities and collections must be marked virtual in your POCOs:
public class Mileage
{
public int Id { get; set; }
public DateTime MileageDate { get; set; }
public string RecordedMileage { get; set; }
//Navigation Properties
public int VehicleId { get; set; }
public virtual Vehicle Vehicle { get; set; }
}
public class Vehicle
{
public Vehicle()
{
Mileages = new List<Mileage>();
}
public int Id { get; set; }
public string Registration { get; set; }
public string Make { get; set; }
public string Model { get; set; }
public Marked Marked { get; set; }
public virtual ICollection<Mileage> Mileages { get; set; }
}
The proxy creation and lazy loading turned on, but that's the default in EF6.
https://msdn.microsoft.com/en-us/data/jj574232.aspx
Let me know if this works.

Answer 2

Well after a lot of searching I managed to find a solution. I used the following:
[HttpGet]
public IEnumerable<VehicleDto> Get()
{
var query = _context.Vehicles.Select(v => new VehicleDto
{
Registration = v.Registration,
Make = v.Make,
Model = v.Model,
Marked = v.Marked,
Mileages = v.Mileages.Select(m => new MileageDto
{
MileageDate = m.MileageDate,
RecordedMileage = m.RecordedMileage
})
.ToList(),
})
.ToList();
return (IEnumerable<VehicleDto>) query.AsEnumerable();
this doesn't seem to be the most elegant way of doing this, if anyone could offer any advice but it does return what is required.
The DTO's look like:
public class VehicleDto
{
public string Registration { get; set; }
public string Make { get; set; }
public string Model { get; set; }
public Marked Marked { get; set; }
public ICollection<MileageDto> Mileages { get; set; }
}
and
public class MileageDto
{
public DateTime MileageDate { get; set; }
public string RecordedMileage { get; set; }
}
Thanks for taking the time to look at this
Tuppers