Entity Framework: Inserting objects with parent/child relationships

Test model:

Code to add a person object and associated addresses:

using (Model1Container mctx = new Model1Container())
            {
                Person person = new Person();
                person.Name = "Raj";

                Address address1 = new Address();
                address1.Line1 = "Line 1";

                person.Addresses.Add(address1);

                Address address2 = new Address();
                address2.Line1 = "Line 2";

                person.Addresses.Add(address2);

                mctx.People.AddObject(person);

                mctx.SaveChanges();
            }

Once SaveChanges is called, all objects (person, address1, address2) will all have the updated Id values, which can be used for other purposes in your code.