Linq To Entities 'Only primitive types or enumeration types are supported' Error

Question

I am using LinqPad to test my query. This query works when the LInqPad connection is to my database (LInq to SQL) but it does not work when I change the connection to use my

Answer 1

If the relationship already exists.

Why not simply say.

var q = from pd in PlanDetails
        select new {
            pd.PlanDetailID,
            ThePlanName = pd.Plan.PlanName
        };

Of course i'm assuming that every PlanDetail will belong to a Plan.

Update

To get better results from LinqPad you could tell it to use your own assembly (which contains your DbContext) instead of the default Datacontext it uses.