You are implementing a method that uses Entity Framework-generated entities. This method creates a new Product entity. You need to associate the Product with a parent Supplier entity and ensure that the Product entity is inserted when you call the ObjectContext's SaveChanges method to persist changes.

What should you do?

To add EntityFramework-generated entities, call the Add method on EntityCollection. For Entity Framework -generated entities and POCO proxy objects, added entities are attached to the context when the principal object is attached.

Call the ObjectContext's Attach method to add a detached object to the ObjectContext and set the object to the Unchanged state. In the Unchanged state, the Entity Framework treats the entity key values as final. The attached entity will not have the Added state and the object will not be inserted when SaveChanges is called.