[英]NHibernate custom collection type
I'm having an entity object called Patient
and this entity is having a property called Visits
which is of type VisitsCollection
. 我有一个名为
Patient
的实体对象,这个实体有一个名为Visits
的属性,其类型为VisitsCollection
。
VisitsCollections
is a child class of IList<Visit>
but it also adds some custom logic to the collection (like auto ordering, some validation, notifications, etc..). VisitsCollections
是IList<Visit>
的子类,但它也为集合添加了一些自定义逻辑(如自动排序,一些验证,通知等)。
I need to use the custom collection type as it adds some data to the entities that are added to the collection and performs some other paperwork transparently. 我需要使用自定义集合类型,因为它会将一些数据添加到添加到集合中的实体,并透明地执行其他一些文书工作。
Now I want to map that in NHibernate, so I've created: 现在我想在NHibernate中映射它,所以我创建了:
<list name="Visits" lazy="true" fetch="select">
<key foreign-key="PatientId" />
<index column="Timestamp" />
<one-to-many class="Visit" not-found="ignore"/>
</list>
I'm getting an exception: 我得到一个例外:
Unable to cast object of type 'NHibernate.Collection.PersistentList' to type '...VisitsCollection'
无法将'NHibernate.Collection.PersistentList'类型的对象强制转换为'... VisitsCollection'
Whenever I'm accessing the visits property. 每当我访问访问属性。
I've also tried to map it this way: 我也尝试过以这种方式映射它:
<list name="Visits" lazy="true" fetch="select" collection-type="VisitsCollection">
<key foreign-key="PatientId" />
<index column="Timestamp" />
<one-to-many class="Visit" not-found="ignore"/>
</list>
but still, I'm getting this exception: 但是,我还是得到了这个例外:
Custom type does not implement UserCollectionType: .....VisitsCollection
自定义类型未实现UserCollectionType:..... VisitsCollection
I don't want to inherit my VisitsCollection
from any NHibernate type as the collection class is part of a framework that I want it to be DAL-agnostic (as it will be used in many scenarios - not only with a database). 我不想从任何NHibernate类型继承我的
VisitsCollection
,因为集合类是我希望它与DAL无关的框架的一部分(因为它将在许多场景中使用 - 不仅仅用于数据库)。
Any ideas on how to map this, preserving the structure of my code? 关于如何映射这个,保留我的代码结构的任何想法?
Thanks in advance. 提前致谢。
I never use custom collection types, mainly because I'm lazy. 我从不使用自定义集合类型,主要是因为我很懒。 NHibernate wants you to use a IUserCollectionType I believe, which requires a bit of plumbing.
NHibernate希望你使用我相信的IUserCollectionType,这需要一些管道。
Rather than that, my first stop would be to look at using extension methods as discussed by Billly McCafferty . 而不是那样,我的第一站是看Billly McCafferty所讨论的使用扩展方法。 But you have code written so...
但你有代码写的......
Alternatively, you could map your collection as a component as discussed here by Colin Jack . 或者,您可以将您的集合映射为组件,如Colin Jack所述 。 This might be easier for your scenario?
对于您的方案,这可能更容易?
I also vote up not to use custom collections. 我也投票不使用自定义集合。 Anyway, you can do it via component.
无论如何,你可以通过组件来做到这一点。
<component name="Warehouses" class="Core.Domain.Collections.EntitySet`1[Core.Domain.OrgStructure.IWarehouseEntity,Core],Core">
<set name="_internalCollection" table="`WAREHOUSE`" cascade="save-update" access="field" generic="true" lazy="true" >
<key column="`WarehouseOrgId`" foreign-key="FK_OrgWarehouse" />
<!--This is used to set the type of the collection items-->
<one-to-many class="Domain.Model.OrgStructure.WarehouseEntity,Domain"/>
</set>
How to map NHibernate custom collection with fluentNHibernate? 如何使用fluentNHibernate映射NHibernate自定义集合?
Just for reference, here is how you could do it using FluentNHibernate
仅供参考,以下是使用
FluentNHibernate
Whether we should or should not create a custom collection type is a separate topic IMHO 我们是否应该创建自定义集合类型是一个单独的主题恕我直言
public class PatientOverride : IAutoMappingOverride<Patient>
{
public void Override(AutoMapping<Patient> mapping)
{
mapping.Component(
x => x.Visits,
part =>
{
part.HasMany(Reveal.Member<VisitsCollection, IEnumerable<Visit>>("backingFieldName")) // this is the backing field name for collection inside the VisitsCollection class
.KeyColumn("PatientId")
.Inverse(); // depends on your use case whether you need it or not
});
}
}
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