如何将Skip和Take附加到nHibernate IQueryOver

Question

我想做这个:

NHibernate.IQueryOver<DataAccess.Domain.Product, DataAccess.Domain.Product> query = session.QueryOver<DataAccess.Domain.Product>();
query = query.Where(x => x.Name == "X");
query = query.Take(1).Skip(3);
List<Product> results = query.List().ToList();

我无法在Skip或Take上找到任何帮助.工具提示帮助(是的,我是绝望的)说Skip和Take返回IQueryOver,但是错误消息说明了"无法隐式地将IQueryOver {T}转换为IQueryOver {T,T}."我不知道IQueryOver是什么{T,T}是.无论如何,我没有要求其中一个.

Answer 1

尝试像这样更改您的代码：

NHibernate.IQueryOver<DataAccess.Domain.Product> query = session.QueryOver<DataAccess.Domain.Product>();
query = query.Where(x => x.Name == "X");
query = query.Take(1).Skip(3);
var results = query.List();

或者，甚至更好：

var results = session.QueryOver<DataAccess.Domain.Product>()
       .Where(x => x.Name == "X")
       .Take(1)
       .Skip(3)
       .List();

您可以在此处下载NHibernateQueryOver检查我的代码。

更新：

我认为你错过了一些东西。我建议您阅读这篇文章，它对我来说非常有帮助。在关于关联的
段落中，他们说：

IQueryOver 有两种类型的兴趣；根类型（查询返回的实体的类型）以及正在查询的“当前”实体的类型。例如，以下查询使用联接创建子 QueryOver（类似于在 ICriteria API 中创建子标准）：

IQueryOver<Cat,Kitten> catQuery =
    session.QueryOver<Cat>()
        .JoinQueryOver(c => c.Kittens)
            .Where(k => k.Name == "Tiddles");

JoinQueryOver 返回 IQueryOver 的新实例，其根位于 Kittens 集合中。限制的默认类型现在是 Kitten（限制上例中的名称“Tiddles”），而调用 .List() 将返回 IList。IQueryOver 类型继承自 IQueryOver。

当我想构建多个过滤器时，我会这样做：

Domain.OrderAddress addressDestination = null;
Domain.Customer customer = null;
Domain.TermsConditionsOfSale termsConditionsOfSale = null;

ICriterion filter1 = Restrictions.Where<Domain.Order>(t => t.Company == "MYCOMPANY");
ICriterion filter2 = Restrictions.Where<Domain.Order>(t => t.WareHouseDelivery == "DEPXX");
ICriterion filter3 = Restrictions.Where<Domain.Order>(t => t.Status == "X");
ICriterion filter4 = Restrictions.Where(() => addressDestination.AddressType == "99");
ICriterion filter5 = Restrictions.Where(() => addressDestination.Province.IsIn(new string[] { "AA", "BB", "CC" }));
ICriterion filter6 = Restrictions.Where(() => termsConditionsOfSale.ReturnedGoodsCode != "01");

var ordersForProvinces = session.QueryOver<Domain.Order>()
    .Inner.JoinAlias(t => t.OrderAddresses, () => addressDestination)
        .Inner.JoinAlias(t => t.Customer, () => customer)
        .Left.JoinAlias(t => t.TermsConditionsOfSale, () => termsConditionsOfSale);

ordersForProvinces
    .Where(filter1)
        .And(filter2)
        .And(filter3)
        .And(filter4)
        .And(filter5)
        .And(filter6);

var Results = ordersForProvinces.Skip(50).Take(20).List();

更新-更新：

NHibernate.IQueryOver<Domain.Person> person = session.QueryOver<Domain.Person>();
var myList = DoSomething(person);

方法：

private static IList<Domain.Person> DoSomething(NHibernate.IQueryOver<Domain.Person> persons)
{
    ICriterion filter1 = Restrictions.Where<Domain.Person>(t => t.CompanyName.IsLike("Customer%"));

    persons.RootCriteria.Add(filter1);
    var x = persons.Skip(1).Take(3).List();
    return (x);
}