"At least one SSDL artifact is required for creating StoreItemCollection" Error with Entity Framework

Question

I have recently been getting this error on my ASP.NET MVC project that uses the Entity Framework:

At least one SSDL artifact is required for creating StoreItemCollection

The error occurs when I try to query the database in a controller action. Has anyone seen this error before? It only occurs every once in a while for me but I am looking for ways to resolve it.

EDIT: I am using Visual Studio 2008 SP1 so the version of Entity Framework should be version 1. I have also tried regenerating the EDMX file which has not helped.

Answer 1

Well, SSDL is part of your EDMX. It's recreated from scratch when you do an "Update Model from Database" in the GUI designer. So the first thing I'd do if I saw this is to connect to a DB with a known good schema and update model.

Answer 2

I believe the issue was being caused by the pattern I was using with my ObjectContext. I was using a Singleton, which just didn't apply well with the ASP.NET MVC framework. I believe the ObjectContext was being disposed when I tried to use it again, hence the error.

I have moved to more of an 'ObjectContext Per Http Request' pattern, as described in this blog post. So far, this has worked much better.