NHibernate QueryOver [英] NHibernate QueryOver

问题描述

我有对象C，它拥有一个对象L的列表，对象C也拥有一个对象C引用R类。

从对象LI中找到对象R。

我试图做这个，但是我只使用这个代码得到null：

L已经是一个函数接收的实例对象。

  var t = SessionController.CurrentSession.QueryOver< C>（）
 .Where（c => c。 （c => cR）
 .Select（c => cR）.SingleOrDefault（）; 
  

不知道我在做什么错在这里将不胜感激。
谢谢

解决方案

问题是您的SingleOrDefault调用正在返回类C的一个实例，我猜测而不是类C的实例，它具有关联类R的Id。您将希望如下修改您的查询：

  （c => c.Id == L.C_Id）
 .JoinQueryOver R（c => cR）
 .Select（c => cR）.SingleOrDefault< R>（）; 
  

请注意SingleOrDefault调用的显式类型。

I've searched around but not found what I am doing wrong here.

I have object C which holds a list of object L, object C also holds a reference to class R.

From object L I want to find object R.

I'm trying to do this but I only get null using this code:

L is already an instanced object a function receives.

var t = SessionController.CurrentSession.QueryOver<C>()
  .Where(c => c.Id == L.C_Id)
  .JoinQueryOver<R>(c => c.R)
  .Select(c => c.R).SingleOrDefault();

Any idea what I'm doing wrong here would be appreciated. Thanks

解决方案

The problem is your SingleOrDefault call is returning an instance of class C and I'm guessing there is not instance of class C that has the Id of the associated class R. You'll want to modify your query as follows:

var t = SessionController.CurrentSession.QueryOver<C>()
  .Where(c => c.Id == L.C_Id)
  .JoinQueryOver<R>(c => c.R)
  .Select(c => c.R).SingleOrDefault<R>();

Note the explicit typing of the SingleOrDefault call.

这篇关于NHibernate QueryOver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！