ASP.Net Layered app - Joint entity data structure among layers

Question

How can I share an auto-generated object data model (generated object classes) among all layers of my C # web application, only providing access to the request in the data layer? It uses a typical three-layer approach: data, business, presentation.

My data layer returns IEnumerable<T>to my business layer, but I cannot return type T to the presentation layer, because I do not want the presentation layer to know about the existence of the data layer, where my entity classes are automatically located.

It is recommended that you have a separate layer with the data model only, but I'm not sure how to separate the data model from the query functionality provided by the entity infrastructure.

Answer 1

If you use POCO objects (.NET 4+) then this is easy (or at least simpler). Is it possible?

You can create a DTO, as Ben said, but then you basically wrap and duplicate each of the objects. EF2 will create crazy objects and dynamically add change tracking, lazy loading, etc., if you wish.

. Entity Framework, , . DTO. EF 1 EF 2 POCO. http://automapper.codeplex.com/

: , :

• MS: http://msdn.microsoft.com/en-us/library/bb738470.aspx
• POCO: http://blogs.msdn.com/adonet/pages/walkthrough-poco-template-for-the-entity-framework.aspx
• POCO, , : http://blogs.msdn.com/adonet/pages/feature-ctp-walkthrough-poco-templates-for-the-entity-framework.aspx
• POCO: http://blogs.msdn.com/adonet/archive/2009/12/22/poco-proxies-part-1.aspx
• : http://blogs.msdn.com/adonet/archive/2008/11/25/working-with-large-models-in-entity-framework-part-2.aspx
• Employee Tracker (, , , ..): http://code.msdn.microsoft.com/ef4/Release/ProjectReleases.aspx?ReleaseId=4279

Answer 2

DTOs DTO rpesentation.