EF Core Include() doesn't query all childs - entity-framework

Question

I have this model:
public class RepairRequest
{
[Key]
public int Id { get; set; }
public List<RepairAction> RepairActions { get; set; }
public decimal TotalPrice => RepairActions.Sum(r => r.ActionPrice);
public string LastOperation => RepairActions.LastOrDefault().RepairOperation.Description;
}
public class RepairAction
{
[Key]
public int Id { get; set; }
public int RepairRequestId { get; set; }
public RepairRequest RepairRequest { get; set; }
public int RepairOperationId { get; set; }
public RepairOperation RepairOperation { get; set; }
public decimal ActionPrice { get; set; }
}
public class RepairOperation
{
[Key]
public int Id { get; set; }
public string Description { get; set; }
}
I'm trying to query RepairRequests and get TotalPrice and also LastOperation in a List but doesn't work for both properties. This is what I have tried till now:
using (var context = new ServiceManagerContext(new DbContextOptions<ServiceManagerContext>())) {
var data = context.RepairRequests
.Include(r => r.RepairActions).ThenInclude(r => r.RepairOperation); // Only LastAction works
//.Include("RepairActions").Include("RepairActions.RepairOperation"); // Only LastAction works
//.Include(r => r.RepairActions); // Only TotalPrice works
//.Include("RepairActions"); // Only TotalPrice works
var repairRequest = data.FirstOrDefault(r => r.Id == 5);
Assert.NotNull(repairRequest);
Assert.Equal(60.0m, repairRequest.RepairPrice);
Assert.Equal("Παραδόθηκε", repairRequest.LastAction);
}
Thank you.

Answer 1

I'd consider avoiding attempting to resolve calculated properties in your domain entities and instead look to resolve those when querying the data to populate view models.
If your view model needs the TotalPrice and LastOperation, then provided a Repository or such returning IQueryable you can expand the query to return what is needed using deferred execution rather than attempting to rely on eager loading the entire tree:
I.e.
IQueryable<RepairRequest> requests = context.RepairRequests.Where(x => x.Id == 5); // Or pull from a Repository returning the IQueryable
var viewModelData = requests.Select(x => new {x.Id, TotalPrice = x.RepairActions.Sum(), LastOperation = x.RepairActions.LastOrDefault()?.RepairOperation?.Description }).SingleOrDefault();
This should execute a more optimized query and return you an anonymous type with just the data you need to populate whatever view model you want to display. The iffy bit is around situations where there are no repair actions, or a repair action without an operation.. EF should avoid the null ref and just return null. the ?. syntax may not be necessary or supported, so it may just need to be ".". Using a method where you eager or lazy load those related entities and execute Linq off the entity instances, be careful around .SingleOrDefault() and drilling down into child fields.

Answer 2

Firstaball you have to declare Foreign Keys, and flag virtual properties like :
public class RepairRequest
{
[Key]
public int Id { get; set; }
public virtual ICollection<RepairAction> RepairActions { get; set; }
public decimal TotalPrice => RepairActions.Sum(r => r.ActionPrice);
public string LastOperation => RepairActions.LastOrDefault().RepairOperation.Description;
}
public class RepairAction
{
[Key]
public int Id { get; set; }
public decimal ActionPrice { get; set; }
public int RepairRequestId { get; set; }
[ForeignKey("RepairRequestId ")]
public virtual RepairRequest RepairRequest { get; set; }
public int RepairOperationId { get; set; }
[ForeignKey("RepairOperationId")]
public RepairOperation RepairOperation { get; set; }
}
Then you could call this, which load all children values :
var data = context.RepairRequests.Include("RepairActions.RepairOperation");