A: 

You can get this error if your underlying 'User' table doesn't have a primary key identified. How is your entity set up (EF, LINQ-to-SQL, etc.) and what's your underlying repository (SQL, etc.)? I'll update my answer accordingly. Hope this helps!

David Hoerster  2010-08-02 17:07:25
That link solved the problem. thx
crauscher  2010-08-02 17:14:19
Great! Glad I could help.
David Hoerster  2010-08-02 17:15:33

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