linq - Entity Framework - "Unable to create a constant value of type 'Closure type'..." error

Question

Why do I get the error:

Unable to create a constant value of type 'Closure type'. Only primitive types (for instance Int32, String and Guid) are supported in this context.

When I try to enumerate the following Linq query?

IEnumerable<string> searchList = GetSearchList();
using (HREntities entities = new HREntities())
{
   var myList = from person in entities.vSearchPeople
   where upperSearchList.All( (person.FirstName + person.LastName) .Contains).ToList();
}

Update: If I try the following just to try to isolate the problem, I get the same error:

where upperSearchList.All(arg => arg == arg) 

So it looks like the problem is with the All method, right? Any suggestions?

Answer 1

It looks like you're trying to do the equivalent of a "WHERE...IN" condition. Check out How to write 'WHERE IN' style queries using LINQ to Entities for an example of how to do that type of query with LINQ to Entities.

Also, I think the error message is particularly unhelpful in this case because .Contains is not followed by parentheses, which causes the compiler to recognize the whole predicate as a lambda expression.