How does Entity Framework work with recursive hierarchies? Include() seems not to work with it

Question

I have an Item. Item has a Category.

Category has ID, Name, Parent

Answer 1

@parliament gave me an idea for EF6. Example for Category with Methods to load all parents up to root node and all children.

NOTE: Use this only for non performance critical operation. Example with 1000 nodes performance from http://nosalan.blogspot.se/2012/09/hierarchical-data-and-entity-framework-4.html.

Loading 1000 cat. with navigation properties took 15259 ms 
Loading 1000 cat. with stored procedure took 169 ms

Code:

public class Category 
{
    [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int Id { get; set; }

    public string Name { get; set; }

    public int? ParentId { get; set; }

    public virtual Category Parent { get; set; }

    public virtual ICollection Children { get; set; }

    private IList allParentsList = new List();

    public IEnumerable AllParents()
    {
        var parent = Parent;
        while (!(parent is null))
        {
            allParentsList.Add(parent);
            parent = parent.Parent;
        }
        return allParentsList;
    }

    public IEnumerable AllChildren()
    {
        yield return this;
        foreach (var child in Children)
        foreach (var granChild in child.AllChildren())
        {
            yield return granChild;
        }
    }   
}