Expression type not supported: System.Linq.Expressions.TypedParameterExpression

Question

I am working on a project. I have the following Model

public class RegistrantClass : IRavenEntity
{
   public RegistrantClass()
   {
       RegistrantId = new List<string>();
   }
   public int Id { get; set; }

   public IList<String> RegistrantId { get; set; }

   public String ClassId { get; set; }
}

And I have the following index defined

        store.DatabaseCommands.PutIndex("RegistrantClass/ClassByStudents",
                            new IndexDefinitionBuilder<RegistrantClass>
                            {
                                Map = students => from i in students
                                                  from j in i.RegistrantId
                                                  select new { j }
                            });

I try to query the above index like so

public object GetMapping(string registrantId)
{
 var mapping = _session.Query<RegistrantClass>("RegistrantClass/ClassByStudents")
                             .Customize(i => i.Include<RegistrantClass>(k => k.RegistrantId))
                             .Customize(i => i.Include<RegistrantClass>(k => k.ClassId))
                             .FirstOrDefault(m => m.registrantId.Contains(registrantId));
return mapping;
}

But then i get the Error Message

However that gives me NotSupportedException: Method not supported: Contains.

I tried with the following code

 .FirstOrDefault(m => registrantId.In<string>(m.RegistrantId));

But then I get the following Error Message

Expression type not supported: System.Linq.Expressions.TypedParameterExpression

What could Me Be Doing Wrong. Kind Regards

Answer 1

You need to do it the other way around:

Not:

.FirstOrDefault(m => registrantId.Contains(m.RegistrantId));

But:

.FirstOrDefault(m => m.RegistrantId.In(registrantId));