Question

I’ve noticed that, by default, Entity Framework Code First neglects to instantiate ICollection<T> properties unless there is at least one item in the collection. I would much prefer that the collection were guaranteed to always be an empty HashSet (i.e., a HashSet with zero items) rather than null if no items exist.

Is there any convention or setting for EF Code First that would enable this?

Answer 1

in the constructor of the entity just set instantiate the collection:

public sealed partial class EntityClass
{
    [SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors",
        Justification = "EF 4.1 requires them to be virtual, and RIA Services requires the collections to be instantiated.")]
    public EntityClass()
    {
        OtherEntities = new List<OtherEntity>();
    }

    public virtual ICollection<OtherEntity> OtherEntities { get; set; }
}

The suppression message is there for FXcop.