Navigation properties not loading properly

问题

My context looks like:

public class ApplicationDbContext: IdentityDbContext<ApplicationUser>
{
    public ApplicationDbContext()
        : base("DefaultConnection")
    {
        this.Configuration.LazyLoadingEnabled = true;
    }

    //DbSet properties
}

so, lazy loading is enabled.

I have following class:

public class Home
{
    private ICollection<Slide> _slides;

    [Key]
    [Required]
    public string Name { get; set; }

    [ForeignKey("Header")]
    public int? HeaderID { get; set; }

    //Navigation properties
    public ICollection<Slide> Slides
    {
        get { return _slides ?? (_slides = new List<Slide>()); }
        set { _slides = value; }
    }

    public Content Header { get; set; }
}

Note that both navigation properties Header and Slides are used without virtual keyword. As far as I know when we don't use virtual keyword - properties should load eagerly.

However, when I get my Home entity from database, both my navigation properties are null (but property HeaderID has value).
Even if I switch to this.Configuration.LazyLoadingEnabled = false; - preperties not loaded - they still null.

Here is how I get my data from db (using repository pattern):

public static Home GetHomeComponent(
    this IRepositoryAsync<Home> repository)
{
   var result = repository
       .Query()
       .Select()
       .First();
   return result;
}

I solved my problem with Include properties:

public static Home GetHomeComponent(
    this IRepositoryAsync<Home> repository)
{
   var result = repository
       .Query()
       .Include(x => x.Header)
       .Include(x=>x.Slides)
       .Select()
       .First();
   return result;
}

However it's not convenient for me (since I have too much navigation properties to load).

So, my question is:
I don't use virtual keyword - but why my navigation properties not loading eagerly?
Or I'm doing something wrong? Is there any other way to load my navigation properties without using Include?

回答1:

If you don't use the virtual keyword it only means that once you try to access the non-virtual property it wont be loaded from the database but you will get a Null .

It doesn't mean you will have all the properties of the entities populated right away, to populate Slides for E.G in your code, you have to use .Include() - this is eager loading, to load the property by your self before it used .

You can make a generic function that will populate the required properties by the arguments it gets ( using params ) see here for more details :

EntityFramework Eager Load all Navigation Properties

来源：https://stackoverflow.com/questions/23978532/navigation-properties-not-loading-properly