Thanks for your response. Look at the following post by Tony Seed's and let me know what you think? It looks like using Tony's approach you need less code the client and would work well on a big size project.
Yassin Khan, Dec 20, 2010
One more link, helps to remove conditional check. http://www.codeproject.com/KB/architecture/FactoryPattern.aspx
Sep 07, 2010
Self Tracking Entities are interesting as they have no dependencies of the Entity Framework and the client can be ignorant of the persistance model.
While this is true, there is no free ride and to get all the benefits you most likely end up writing DTOs (or use AutoMapper), just like we do in the DoFactory patterns. The details are very well explained in this article:
We will continue to look into Self Tracking Entities but at this point we have no plans to include these in our next release of Design Pattern Framework.
I hope this answers your question.
Dan McMillan, Dec 12, 2010