[英]NHibernate.Linq - Custom/Calculated property expression
How can a domain object include a property that calculates a value from other database mapped properties so that the calculated property can be used in both the domain object instance and the db level by nhibernate.linq. 域对象如何包含从其他数据库映射属性计算值的属性,以便nhibernate.linq可以在域对象实例和数据库级别中使用计算属性。
I would like to be able to use the property when working with the object directly: 我希望能够在直接使用对象时使用该属性:
Console.WriteLine(Entity.Calculated.ToString());
And when working with nhibernate.linq 当使用nhibernate.linq时
var q = from e in session.Linq<Entity>()
where e.Calculated > 0
select e;
You need to duplicate the logic in the class and the mapping. 您需要复制类和映射中的逻辑。 Here's an example:
这是一个例子:
Class: 类:
public class Invoice
{
public virtual int Id { get; protected set; }
public virtual decimal Amount { get; set; }
public virtual decimal Paid { get; set; }
public virtual decimal Balance
{
get { return Amount - Paid; }
}
}
Mapping: 制图:
<class name="Invoice">
<id name="Id">
<generator class="hilo"/>
</id>
<property name="Amount"/>
<property name="Paid"/>
<property name="Balance" formula="Amount - Paid" access="readonly"/>
</class>
Now you can use Linq and query on Invoice.Balance
现在,您可以在
Invoice.Balance
上使用Linq和查询
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