Convince entity context (EF1) to populate entity references

I have an entity with self reference (generated by Entity Designer):

public MyEntity: EntityObject
{
    // only relevant stuff here
    public int Id { get...; set...; }
    public MyEntity Parent { get...; set...; }
    public EntityCollection<MyEntity> Children { get...; set...; }
    ...
}

I've written a stored procedure that returns a subtree of nodes (not just immediate children) from the table and returns a list of MyEntity objects. I'm using a stored proc to avoid lazy loading of an arbitrary deep tree. This way I get relevant subtree nodes back from the DB in a single call.

List<MyEntity> nodes = context.GetSubtree(rootId).ToList();

All fine. But when I check nodes[0].Children, its Count equals to 0. But if I debug and check context.MyEntities.Results view, Children enumerations get populated. Checking my result reveals children under my node[0].

How can I programaticaly force my entity context to do in-memory magic and put correct references on Parent and Children properties?

UPDATE 1

I've tried calling

context.Refresh(ClientWins, nodes);

after my GetSubtree() call which does set relations properly, but fetches开发者_Python百科 same nodes again from the DB. It's still just a workaround. But better than getting the whole set with context.MyEntities().ToList().

UPDATE 2

I've reliably solved this by using EF Extensions project. Check my answer below.

You need to assign one end of the relationship. First, divide the collection:

var root = nodes.Where(n => n.Id == rootId).First();
var children = nodes.Where(n => n.Id != rootId);

Now, fix up the relationship.

In your case, you'd do either:

foreach (var c in children)
{
    c.Parent = root;
}

...or:

foreach (var c in children)
{
    root.Children.Add(c);
}

It doesn't matter which.

Note that this marks the entities as modfied. You'll need to change that if you intend to call SaveChanges on the context and don't want this saved.

The REAL solution

Based on this article (read text under The problem), navigation properties are obviously not populated/updated when one uses stored procedures to return data.

But there's a nice manual solution to this. Use EF Extensions project and write your own entity Materilizer<EntityType> where you can correctly set navigation properties like this:

...
ParentReference = {
    EntityKey = new EntityKey(
        "EntityContextName.ParentEntitySetname",
        new[] {
            new EntityKeyMember(
                "ParentEntityIdPropertyName",
                reader.Field<int>("FKNameFromSP")
            )
        })
}
...

And that's it. Calling stored procedure will return correct data, and entity object instances will be correctly related to eachother. I advise you check EF Extensions' samples, where you will find lots of nice things.