nhibernate queryOver 投影语法
我正在尝试 NH 3.0 Cookbook 中的一些代码，并想知道为什么我无法编译下面的代码。我认为应该使这项工作的 QueryProjectionBuilder 位于“NHibernate.Criterion.Lambda”中，但它的 using 指令没有帮助。
问题在于 SelectGroup 和 SelectAvg 部分。假设书中的语法是正确的，有人能看到这里缺少的参考吗？
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]
});
}
}
}
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]
});
}
}
}
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评论（1）
您必须使用
.SelectList而不是.SelectYou have to use
.SelectListinstead of.Select