CODEWITHSUNDEEP
c#entity-frameworkiqueryable
Robbe R
Robbe R

Reputation: 23

Include 2 entities in 1

I have an entity Auto (car)

public class Auto : BaseDbEntity
{
    public string Kleur { get; set; }
    public DateTime DatumGekocht { get; set; }
    public string Nummerplaat { get; set; }
    //relations
    public Eigenaar HuidigeEigenaar { get; set; }
    public AutoType HuidigeAutoType { get; set; }
}

And 2 entities linked to this one, Eigenaar (owner) and AutoType

public class Eigenaar : BaseDbEntity
{
    public string Voornaam { get; set; }
    public string Achternaam { get; set; }
    public string Naam => $"{Voornaam} {Achternaam}";
}

public class AutoType : BaseDbEntity
{
    public string Merk { get; set; }
    public string Model { get; set; }
}

In my AutoDataService I have the following:

public List<Auto> GetAllAutosSortedByName(AutoCriteria criteria)
{
    return GetFullyGraphedAutos()
        .Where(x => string.IsNullOrEmpty(criteria.Name))
        .OrderBy(x => x.Id).ToList();
}

private IIncludableQueryable<Auto, AutoType> GetFullyGraphedAutos()
{
    return _entityContext.Autos.Include(x => x.HuidigeAutoType);
}

This way I have the AutoType entity linked to the main Auto entity. But I can't figure out how to also link the 3rd entity "Eigenaar" since IIncludableQueryable only allows for 2 parameters.

I would assume it needs to look something like this

private IIncludableQueryable<Auto, AutoType, Eigenaar> GetFullyGraphedAutos()
{
    return _entityContext.Autos.Include(x => x.HuidigeAutoType).thenInclude(x => x.HuidigeEigenaar);
}

Obviously this doesn't work, is there another function I should use to accomplish this?

Upvotes: 0

Views: 110

Answers (1)

Camilo Terevinto
Camilo Terevinto

Reputation: 32063

You should not depend explicitly on IIncludableQueryable, just continue to return IQueryable to follow the conventions of LinQ:

private IQueryable<Auto> GetFullyGraphedAutos()
{
    return _entityContext.Autos
        .Include(x => x.HuidigeAutoType)
        .Include(x => x.HuidigeEigenaar);
}

I will also suggest you to use the asynchronous version of the I/O bound methods of DbContext (the ones that actually execute the query, like ToList, First, etc), specially given that you are working on a web application:

public async Task<List<Auto>> GetAllAutosSortedByNameAsync(AutoCriteria criteria)
{
    return await GetFullyGraphedAutos()
        .Where(x => string.IsNullOrEmpty(criteria.Name))
        .OrderBy(x => x.Id)
        .ToListAsync();
}

Upvotes: 1

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