Question

I have the code below (this is actually part of a much more complicated query, but I have isolated the issue to this particular line to help with debugging) which per everything I have read should create an IN clause in SQL, assuming I am using EF4. As far as I can tell, I am using EF4 (We are using .NET Framework 4 for our projects and when I look at the System.Data and System.Data.Entity they both say version 4.0.0.0 for all the projects)

int[] assessmentIDs; // this is just here to show what this is, 
                     // but it is a params parameter passed to this methed                  

var assessments = from cert in container.ProctorAssessmentCertifications
                  where assessmentIDs.Contains(cert.AssessmentID)
                  select cert.ID;

However, when I run this, I get the runtime error:

LINQ to Entities does not recognize the method 'Boolean Contains[Int32](Int32[], Int32)' method, and this method cannot be translated into a store expression.

When I use LinqPad, it does correctly output an IN clause like one would expect in EF4.
My questions are:

A. What am I doing wrong and how do I make this work?

B. How do I force EF4 to be called if in fact it’s not? I can find no reference in any web.config file that point it to the older version.

Answer 1

Contains does not get translated into valid SQL because assessmentIDs is not IQueryable, it is an in-memory object. So you’ll have to pull the data out first, and then do the check.

var assessments = (from cert in container.ProctorAssessmentCertifications                  
                  select cert.ID).ToList() //no longer IQueryable.

var result = assessments.Intersect(assessmentIDs);