Entity Framework Fluent API ICollection.count (one to many) - entity-framework

Question

I am new to EF and i have the following scenario:
I want to load the IHave apples without loading the whole Apples collection.
The model:
public class Category
{
public virtual ICollection<Classified> Apples { get; set; }
[NotMapped]
public bool IHaveApples {get { return Apples.count > 0; } }
}
And the FLUENT API Config:
public class CategoryConfiguration : EntityTypeConfiguration<Category>
{
public CategoryConfiguration()
{
HasMany(o => o.Apples ).WithRequired().HasForeignKey(o => o.CategoryId);
}
}
And in my controller i go with
//The controller returns IQueryable<Category>
var category = _contextProvider.Context.Categories;
Thanks in advance,
Stelios K.

Answer 1

As IHaveApples is a bool, you should simply use Apples.Any() instead of Count.
EDIT:
If you want this to be automatically set (i.e. the boolean is set without even accessing manually to your collection), what you could do is add an handler to the ObjectMaterialized event:
public class Category
{
...
public bool IHaveApples { get; set; }
}
((IObjectContextAdapter)yourDbContext).ObjectContext.ObjectMaterialized += (sender, e) =>
{
var entityAsCategory = e.Entity as Category;
if (entityAsCategory != null)
{
entityAsCategory.IHaveApples = yourDbContext
.Entry(entityAsCategory)
.Collection(z => z.Apples)
.Query()
.Any();
}
};