I am using the Entity framework to create a new order. The order contains a collection of contacts, a many to many relationship. I want to add a reference to an existing contact on the order on creation of the order. Both Order and Contact a Entity Objects.
Order order = new Order();
//set details on order
Contact contact = new Contact();
EntityKey contactKey =
new EntityKey("OrderDetails.Contact",
"contact_id", contact.Key.Id);
contact.EntityKey = contactKey;
contact.contact_id = contact.Key.Id;
order.Contact.Attach(contact); // throws an exception!
OrderDetails ordTable = new OrderDetails();
ordTable.AddToOrder(order);
int result = orgTable.SaveChanges();
When I go to attach, this exception is thrown:
"Attach is not a valid operation when the source object associated with this related end is in an added, deleted, or detached state. Objects loaded using the NoTracking merge option are always detached."
I know I'm probably missing a step or not fully understanding how the entity framework handles many-to-many relationships.