Entity framework POCO - Update collection

Question

i have a simple model with classes named customer and address like this:

public class Customer : BusinessEntity
{
    public string FirstName { get; set; }

    public string LastName { get; set; }

    public DateTime? DateOfBirth { get; set; }

    public decimal? CreditLimit { get; set; }

    public virtual List<Address> Addresses { get; set; }

    public string Email { get; set; }
}

public class Address : BusinessEntity
{
    public string Street { get; set; }

    public string Floor { get; set; }

    public Customer Customer { get; set; }
}

I wrote a unit test that loads a customer with an existing address, modifies that address and calls update. Here's the code:

        Customer newCustomer = new Customer();

        newCustomer.FirstName = "Cosme";

        newCustomer.LastName = "Fulanito";

        newCustomer.Email = "anemail@mail.com";

        customerPersistence.Save(newCustomer);

        Customer existingCustomer = customerPersistence.FindByID(newCustomer.ID.Value);

        Assert.IsNotNull(existingCustomer, "Customer not found after saving");

        existingCustomer.LastName = "Fulanito Modified";

        existingCustomer.Addresses = new List<Address>();

        existingCustomer.Addresses.Add(new Address { Customer = existingCustomer, Floor = "21", Street = "Peron" });

        customerPersistence.Update(existingCustomer);

        Customer loadedCustomer = customerPersistence.FindByID(newCustomer.ID.Value);

        Assert.IsNotNull(loadedCustomer, "Customer not found after updating");

        Assert.IsTrue(loadedCustomer.LastName == existingCustomer.LastName, "Last name not updated");

        Assert.IsNotNull(loadedCustomer.Addresses, "Addresses collection is null");

        Assert.IsTrue(loadedCustomer.Addresses.Count > 0, "Addresses collection is empty");

        existingCustomer = customerPersistence.FindByID(newCustomer.ID.Value);

        Assert.IsNotNull(existingCustomer, "Customer not found after updating");

        existingCustomer.Addresses[0].Floor = "40";

        customerPersistence.Update(existingCustomer);

        Assert.IsTrue(loadedCustomer.Addresses[0].Floor == "40", "Address data not modified");

Context is a reference to a class that inherits from DBContext. I'm getting this error:

A relationship from the 'Address_Customer' AssociationSet is in the 'Deleted' state. Given multiplicity constraints, a corresponding 'Address_Customer_Source' must also in the 'Deleted' state.

What am i missing? Is it a problem with the way i'm defining the relationship between Customer and Address in OnModelCreating method? I'm doing this:

modelBuilder.Entity<Address>()
            .HasRequired(p => p.Customer)
            .WithMany(p => p.Addresses)
            .Map(x => x.MapKey("CustomerID"))

Thanks, Gonzalo

@LadislavMrnka I get the customer from the DB and then existingCustomer.Addresses[0].Floor = "40"; — Gonzalo, Jul 11 '12 at 20:26
@TommyGrovnes The exception is thrown when i call SaveChanges. One thing i noticed is that the address collection is emptied when i change the customer entitie's state to "Modified" — Gonzalo, Jul 14 '12 at 16:41
Am I right assuming that Update method of customerPersistence opens session then performs update and closes session? — Rafal, Jul 17 '12 at 05:37
Check this answer : http://stackoverflow.com/questions/6869874/entity-framework-4-1-codefirst-given-multiplicity-constraints-error-when-dele — radu florescu, Jul 18 '12 at 18:32

score 1 · Answer 1 · answered Jul 19 '12 at 04:50

Please change the Addresses Property to ICollection. Then, when you are updating the details, check whether the EntityState is deatched or not. If it is detached then you have to attach the updated object (Customer as well as Address) into the context, and have to tell the ObjectStateManager that the object is modified.

Entity framework POCO - Update collection

1 Answers1