QueryOver如何用于筛选特定的类? [英] How can QueryOver be used to filter for a specific class?

问题描述

我目前正在像这样动态构建查询:

I am currently dynamically constructing queries like so:

QueryOver<Base, Base> q = QueryOver.Of<Base>();

if (foo != null) q = q.Where(b => b.Foo == foo);
// ...

现在我要过滤的Base(例如Derived)有多个映射子类，基本上是这样的:

Now there are multiple mapped subclasses of Base (e. g. Derived) which I want to filter on, basically something like:

if (bar) q = q.Where(b => b is Derived); // does not work

或:

if (bar) q = q.Where(b => b.DiscriminatorColumn == 'derived'); // dito

如何最好地(但不是必须)以类型安全的方式实现这一目标?也可以使用LINQ做到这一点吗?

How do I best achieve that, preferably - but not neccessarily - in a type-safe way? Can this be done using LINQ, too?

推荐答案

这不是 直观的方法，但是以下方法应该可以正常工作(QueryOver):

This is not intuitive, but the following should work fine (QueryOver):

if (bar) q = q.Where(b => b.GetType() == typeof(Derived));

我不确定在LINQ-to-NH中执行此操作的方法.

I'm not sure about a way to do this in LINQ-to-NH.

这篇关于QueryOver如何用于筛选特定的类?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！