entity-framework - 使用 Include 的派生类的急切加载属性

Question

我有这样的类(class):

Person
{
   Name
   Address
}

Employee : Person
{
   Compensation - object
}

Visitor : Person
{

}

如果我写 linq:

var persons = Context.Persons
                .Include("Compensation");

我得到错误:

A specified Include path is not valid. The EntityType 'Person' does not declare a navigation property with the name 'Compensation'.

如果我这样做，它可以正常工作:

var persons = Context.Persons
                .OfType<Employee>()
                .Include("Compensation");

但我想在同一个查询中获取员工和访客。

EF4 UserVoice 上似乎有此功能的请求:
http://data.uservoice.com/forums/72025-ado-net-entity-framework-ef-feature-suggestions/suggestions/1249289-include-property-of-derived-classes?ref=title

但它看起来不会很快完成。

这个问题有什么好的解决方法？

Answer 1

你可以这样试试:

var persons = Context.Persons
                     .OfType<Employee>()
                     .Include("Compensation")
                     .Concat<Person>(Context.Persons.OfType<Visitor>());