NHibernate: how to return root type object in SelectList

Question

My DTO:

public class ServiceWithCount
{
  public Service Service { get; set; }
  public long Count { get; set; }
}

and:

public class Service
{
  public virtual long Id { get; set; }
  ...
}
public class Vote
{
  public virtual long Id { get; set; }
  public virtual Service Service { get; set; }
  ...
}

I would like to do something like:

ServiceWithCount dto = null;
Service serviceAlias = null;

var result = session.QueryOver<Service>(() => serviceAlias)
  .Where(x => x.Serie.Id == serie.Id)
  .SelectList(list =>
    list
      .SelectSubQuery(QueryOver.Of<Vote>().Where(y => y.Service.Id == serviceAlias.Id).ToRowCountInt64Query()).WithAlias(() => dto.Count)
      .Select(x => x).WithAlias(() => dto.Service) //This line causes error
  )
  .TransformUsing(Transformers.AliasToBean<ServiceWithCount>())
  .List<ServiceWithCount>();

but this causes an error:

could not resolve property:  of: MyNamespace.Service

How to return root type object as component of dto?

Answer 1

A solution using Linq:

add the namespace:

using System.Linq;
using NHibernate;
using NHibernate.Linq;

And query something like this:

var result = (from s in session.Query<Service>()
             where s.Serie.Id == serie.Id
             let count = session.Query<Vote>().Count(v => v.Service.Id == s.Id)
             select new ServiceWithCount() { Service = s, Count = count })
             .ToList();

I think exposing your entity Service in the DTO is not a good pratice, you could expose simple properties just to get the information you want to transfer, avoiding the risk to get a proxy from nhibernate inside the DTO.