How to save related new objects that comes from differents DBContext CTP5

I'm working on a MVC3 application and I created my POCO classes from my database with the DbContext Code Generator. All goes fine until I got stuck in this situation. Note that I use the repository pattern and I use for every entity a dedicated repository whether get a new instance of the DbContext.

Now, I'm in this situation:

object A has a relation one-to-many with B (A can have one or many B) object B has a relation many-to-one with C (C can have one or many B) object B has a relation many-to-one with D (D can have one or many B)

I should add a new object B, consider that object C and D are yet existing, so I must only do the relation and the object A can be created or updated. In the specific consider that A is customer and B is subscriptions (C and D are virtual objects properties in B).

Now If I try to save I got duplicates in C and D tables, while the management of the object seems to work. So, I thinked that I should detach the entities before do the relation, but when I call the SaveChanges() I got this error:

Store update, insert, or delete statement affected an unexpected number of rows (0).开发者_如何学编程 Entities may have been modified or deleted since entities were loaded. Refresh ObjectStateManager entries.

Here's the code:

Customer customer = customerRepository.Get(ID);                  
if (customer == null)
{
     customer = new Customer();
     customer.Email = Request.Form["Email"].ToString();
}

Subscription subscription = new Subscription();
subscription.Active = true;
subscription.DateSubscription = DateTime.Today;

Object C = objectCRepository.Get(Request.Form["IDObjectC"]);//Get C object from database
Object D = objectDRepository.Get(Request.Form["IDObjectD"]);//Get D object from database

if (C != null)
{
    //I tried also to detach the objects before adding to subscription
    subscription.C = C;
    subscription.D = D;
    customer.Subscriptions.Add(subscription);

     if (customer.IDCustomer == 0)
         customerRepository.Add(customer);
     else
         UpdateModel(customer);

    customerRepository.Save();
}

And here the add and the save method of the customer repository:

public override void Add(Cliente cliente)
{
   db.Cliente.Add(cliente);
}

public override void Save()
{
  foreach (var entry in db.ChangeTracker.Entries()
               .Where(e => e.State == EntityState.Modified || e.State == EntityState.Added            || e.State == EntityState.Unchanged || e.State == EntityState.Detached))
  {
     string state = ObjectContext.GetObjectType(entry.Entity.GetType()).Name + " " + entry.State.ToString();

  if (ObjectContext.GetObjectType(entry.Entity.GetType()).Name.Equals("C") ||  ObjectContext.GetObjectType(entry.Entity.GetType()).Name.Equals("D"))
  {
     entry.State = EntityState.Unchanged;
  }
  dbContext.SaveChanges();
}

I tried also to use this for objects C and D.

((System.Data.Entity.Infrastructure.IObjectContextAdapter)dbContext).ObjectContext.Refresh(System.Data.Objects.RefreshMode.StoreWins, entry);

And the error received is

The element at index 0 in the collection of objects to refresh has a null EntityKey property value or is not attached to this ObjectStateManager.

I noticed that in CTP5 was added the option AsNoTracking(), I tried to use it, but nothing! I checked also the Concurrency mode for every properties involved in the operation and all are set to None. I finished ideas :(!

Any help would appreciated! Thanks!

---

Actually I solved myself using on loading the AsNoTracking() method and before saving the entities I change the state to Unchanged.

//On loading
Context.Object.AsNoTracking().SingleOrDefault(l => l.Property == Property);

//On saving
Object.State = EntityState.Unchanged;
Object.SaveChanges();

Hope this helps someone.