NHibernate-QueryOver使用基类? [英] NHibernate- QueryOver using base classes?

问题描述

现在我正在使用Criteria API并喜欢它，但是如果我可以切换到QueryOver API，那就更好了.但是，我的设置有些奇怪.为了将数据分区到表中，我有一个基本的抽象类:

Right now I'm using the Criteria API and loving it, but it would be even better if I could make the switch to the QueryOver API. However, my setup is a little strange. In order to partition data into tables, I have one base abstract class:

Listing

以及从其继承的许多类:

and a number of classes which inherit from that:

Listing_UK
Listing_US
etc.

使用标准API，我可以执行以下操作:

With the criteria API, I can do something like:

Type t = typeof(Listing_UK);
if (condition) t = typeof(Listing_US);
DbSession.CreateCriteria(t)
            .Add(Restriction.Eq("field",value)
            .List<Listing>());

基本上，对不同的类使用相同的查询.似乎QueryOver的强类型性质使我无法执行此操作-基本问题是:

Basically, using the same query on different classes. It seems like the strongly-typed nature of QueryOver prevents me from doing this- the basic problem being that:

DBSession.QueryOver<Listing_UK>()

不强制转换为

DBSession.QueryOver<Listing>

虽然我理解为什么，但是我想知道是否有人可以使用任何技巧创建通用的QueryOver，而该OverOver仍然会定位正确的表?

While I understand why, I'm wondering if anyone has any trick I could use to create a generic QueryOver that will still target the right table?

推荐答案

您可能会发现可以使用以下重载:

You might find you could use the following overload:

DbSession.CreateCriteria(myDynamicallyDeterminedType)
    .Add(Restrictions.On<Listing>(l => l.field == value))
    .List<Listing>();

这篇关于NHibernate-QueryOver使用基类?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！