nhibernate queryOver投影语法

Question

I am trying some code out from a NH 3.0 Cookbook, and wondering why I can't get the code below to compile. I think the QueryProjectionBuilder that should make this work is in "NHibernate.Criterion.Lambda" but the using directive for it doesn't help.

The problems are the SelectGroup and SelectAvg parts. Assuming the syntax from the book is correct, can anyone see a missing reference here?

namespace Queries.Implementations
{
using System;
using System.Collections.Generic;
using System.Linq;
using Eg.Core;
using NHibernate;
using NHibernate.Criterion;
using NHibernate.Criterion.Lambda;

    public class QueryOverQueries : CookbookQueriesBase
    {

        public override IEnumerable<NameAndPrice> GetAvgDirectorPrice(ISession session) {
            return _session.QueryOver<Movie>()
                .Select(list => list
                                    .SelectGroup(m => m.Director)
                                    .SelectAvg(m => m.UnitPrice)
                )
                .List<object[]>()
                .Select(props =>
                        new NameAndPrice
                        {
                            Name = (string) props[0],
                            Price = (decimal) props[1]
                        });

        }
    }
}

Answer 1

您必须使用.SelectList而不是.Select