How can I get distinct values using Linq to NHibernate?

Question

Hello,

I've been trying to get distinct values using Linq to NHibernate and I'm failing miserably.

I've tried:

var query = from requesters in _session.Linq<Requesters>()
        orderby requesters.Requestor ascending
        select requesters;

return query.Distinct();

As well as

var query = from requesters in _session.Linq<Requesters>()
        orderby requesters.Requestor ascending
        select requesters;

return query.Distinct(new RequestorComparer());

Where RequestorComparer is

public class RequestorComparer : IEqualityComparer<Requesters>
{

    #region IEqualityComparer<Requesters> Members
    bool IEqualityComparer<Requesters>.Equals(Requesters x, Requesters y)
    {
        //return x.RequestorId.Value.Equals(y.RequestorId.Value);
        return ((x.RequestorId == y.RequestorId) && (x.Requestor == y.Requestor));
    }

    int IEqualityComparer<Requesters>.GetHashCode(Requesters obj)
    {
        return obj.RequestorId.Value.GetHashCode();
    }
    #endregion
}

No matter how I structure the syntax, it never seems to hit the .Distinct(). Without .Distinct() there are multiple duplicates by default in the table I'm querying, on order of 195 total records but there should only be 22 distinct values returned.

I'm not sure what I'm doing wrong but would greatly appreciate any assistance that can be provided.

Thanks

Answer 1

Try reordering to :

var query = from requesters in _session.Linq<Requesters>()

    select requesters;

return query.Distinct().OrderBy(x=>x.Requestor);

I have seen issues with ordering of OrderBy and Distinct.

Let me know if that doesn't work out for you.

Answer 2

Have you tried with the new integrated Linq provider in NH 3.0?

The old one is very limited.