NHibernate，在表之间联接并返回特定类型
NHibernate，在表之间联接并返回特定类型
提问于 2012-11-07 20:05:12
我有两个表，我想把一些字段放在一个结果类中，但是我被卡住了。我想要使用实体框架的代码如下所示：
var res =
(from p in context.EstimationItem
join q in ...
select new EstimationWithDetail
{
Estimation = q.Estimation,
Id = q.Id,
FullName = q.Customer.FirstName + q.Customer.LastName
}).ToList();在Nibernate，现在，我有这个，但是我被困住了.
var res =
Session.QueryOver<EstimationItem>()
.JoinQueryOver(x => x.Estimation)
.Select(
x => x.Estimation.Reference,
x => x.Estimation.CreationDate,
x => x.Price,
x => x.Estimation.Customer.FirstName,
x => x.Estimation.Customer.LastName
)
.List();
public class Estimation
{
public virtual string Reference { get; set; }
public virtual Customer Customer { get; set; }
public virtual DateTime CreationDate { get; set; }
public virtual decimal Total { get; set; }
public virtual IList<EstimationItem> EstimationItems { get; set; }
}
public class EstimationItem
{
public virtual decimal Price { get; set; }
public virtual int Quantity { get; set; }
public virtual Estimation Estimation { get; set; }
public virtual Product Product { get; set; }
}
public class EstimationWithDetail
{
public string Reference { get; set; } //Estimation.Reference
public string FullName { get; set; } //concat FirstName and LastName from Customer
public decimal Price { get; set; } //Estimation.Total
public int Id { get; set; } //Estimation.Id
public DateTime CreationDate { get; set; } //Estimation.CreationDate
}更新1
我尝试了代码，但我得到了以下错误: InvalidOperarionException，变量'x‘类型'EstimationItem’从作用域‘引用’，但它没有定义
var res =
Session.QueryOver<EstimationItem>()
.JoinQueryOver(x => x.Estimation)
.Select(x => new EstimationWithDetail
{
Code = x.Estimation.Reference,
CreationDate = x.Estimation.CreationDate,
Price = x.Estimation.Total,
FullName = x.Estimation.Customer.FirstName + x.Estimation.Customer.LastName
})
.List<EstimationWithDetail>();更新2 :我也尝试过
Estimation a = null;
Customer b = null;
var res = Session.QueryOver<EstimationItem>()
.JoinAlias(c => c.Estimation, () => a)
.JoinAlias(c => c.Estimation.Customer, () => b)
.Select(x => new EstimationWithDetail
{
Code = a.Reference,
Id = a.Id,
FullName = b.LastName
})
.List<EstimationWithDetail>();回答 1
Stack Overflow用户
发布于 2012-11-07 20:11:12
我不太熟悉NHibernate的Linq提供程序，因为我还没有使用它，但是您不能这样做：
var res = Session.QueryOver<EstimationItem>()
.JoinQueryOver(x => x.Estimation)
.Select(x => new EstimationWithDetail
{
Estimation = x.Estimation,
Id = x.Id,
FullName = x.Estimation.Customer.FirstName + x.Estimation.Customer.LastName
})
.List();页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/13277324
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