nhibernate - 如何使用 Fluent NHibernate 映射具有私有(private)作用域的组件？

Question

我有旧模式中的列，我想将其映射为组件(也称为值类型)。对组件/值类型的引用属于私有(private)范围。

实体代码如下所示:

public class Allocation : Entity<int>
{
    //...
    private readonly Money price;

    protected Allocation() {} /* for NH only */

    public Allocation(/* ... */ Money price)
    {
        //...
        this.price = price;
    }
}

值类型代码如下所示:

public struct Money
{
    private readonly decimal amount;
    private readonly int currencyId;

    public Money(decimal amount, int currencyId)
    {
        this.amount = amount;
        this.currencyId = currencyId;
    }
}

当前映射如下所示:

Component(Reveal.Member<Allocation, Money>("price"), 
          p =>
          {
             p.Map(Reveal.Member<Money>("amount")).Column("CURRENCY_PRICE").Not.Nullable();
             p.Map(Reveal.Member<Money>("currencyId")).Column("CURRENCY").Not.Nullable();
          });

目前，上面的代码抛出以下异常:

System.ArgumentException : Expression of type 'System.Object' cannot be used for return type 'BI.IPM.Services.TradeAllocation.Domain.Entities.Money'

Answer 1

用户类型会有所帮助，然后您可以在 NullSafeGet/set 方法中新建 Money 实例。

there's some links to a money usertype in here.