You add code that modifies Entity Framework POCO entities with proxies. You need to create a POCO entity named Customer and ensure that it will be inserted when you call the SaveChanges method of the ObjectContext.

What should you do?

You must use the CreateObject method to create the entity. Creating the entity with this method ensures that the proxy is created.

Add the Customer directly to the entity collection. Use of the proxy will ensure that the insertion is detected when you call SaveChanges.

If you use the new operator the POCO proxy will not be created. The POCO proxy is needed to ensure that the new entity is tracked for insertion when you call SaveChanges.