将依赖项注入实体框架实体和项目

Question

有没有办法将依赖项注入从EF Linq context.Entities.Select(x => new Y {...})投影返回的对象？(我使用的是Simple Injector,但概念仍然存在)

我试图实现的一些事情:(这只是输入,没有编译,抱歉任何语法错误/不完整)

// person MAY be an entity, but probably more likely a class to serve a purpose
public class Person {
  public string Name
  public DateTime DOB {get;set; }

  // what I want to achieve: note, I don't want to have complex logic in my model, I want to pass this out to a Service to determine.. obviously this example is over simplified...
  // this could be a method or a property with a get accessor
  public bool CanLegallyVote()  
  {
    return _someServiceThatWasInjected.IsVotingAge(this.DOB);
  }

  private readonly ISomeService _someServiceThatWasInjected;
  public Person (ISomeService service)
  {
    _someServiceThatWasInjected = service;
  }
}

// then calling code... I can't pass ISomeService into the "new Person", as "Additional information: Only parameterless constructors and initializers are supported in LINQ to Entities."

// If the above model represents a non-entity...
var person = context.People.Select(person => new Person {Name = x.Name, DOB = x.DateOfBirth}).First;
// OR, if the above model represents an EF entity...
var person = context.People.First();

if (person.CanLegallyVote()) {...}

// I don't want to invoke the service from the calling code, because some of these properties might chain together inside the model, I.e. I do not want to do the following:
if (_service.CanLegallyVote(person.DOB))

Linq/Entity Framework中是否有任何钩子允许我将对象(通过DI)传递给创建的模型？

Answer 1

有ObjectContext.ObjectMaterialized事件.你可以勾住它.但一般而言,将域名服务注入域名实体并不是一个好主意.你可以找到很多关于这个主题的文章.

Answer 2

@Oryol是正确的，施工期间，喷射应用程序组件到域对象是一个坏主意，就像它是周围的其他方式。

一种解决方案是使用方法注入而不是构造函数注入。这意味着每个域方法都将其所需的服务定义为方法参数。例如：

public bool CanLegallyVote(ISomeService service) { ... }