ICollection<T>与列表<T>在实体框架中 [英] ICollection<T> Vs List<T> in Entity Framework

问题描述

在我开始设计一些实体框架应用程序之前，我只观看了一些网络广播.我真的没有阅读那么多文档，我觉得我现在正在为此受苦.

I only watched a few webcasts before I went head first in to designing a few Entity Framework applications. I really didn't read that much documentation and I feel like I am suffering for it now.

我一直在课堂上使用 List，效果很好.

I have been using List<T> in my classes, and it has worked great.

现在我阅读了一些文档，它指出我应该使用 ICollection.我改成了这个，它甚至没有引起模型上下文的变化.这是因为 List 和 ICollection 都继承了 IEnumerable，而这才是 EF 实际需要的吗?

Now I have read some documentation and it states that I should have been using ICollection<T>. I changed to this, and it didn't even cause a model context change. Is this because both List<T> and ICollection<T> inherit IEnumerable<T>, and that is what is actually required for EF?

但是，如果是这种情况，为什么 EF 文档没有说明它需要 IEnumerable 而不是 ICollection?

However, if this is the case, why doesn't the EF documentation state that it requires IEnumerable<T> instead of ICollection<T>?

无论如何，我所做的是否有任何缺点，或者我应该改变它吗?

In any case, are there any downsides to what I have done, or should I change it?

推荐答案

Entity Framework 将使用 ICollection 因为它需要支持 Add 操作，这些操作不是IEnumerable 接口的一部分.

Entity Framework would use ICollection<T> because it needs to support Add operations, which are not part of the IEnumerable<T> interface.

另请注意，您正在使用ICollection，您只是将其作为List 实现公开.List 带来了 IList、ICollection 和 IEnumerable>.

Also note that you were using ICollection<T>, you were merely exposing it as the List<T> implementation. List<T> brings along with it IList<T>, ICollection<T>, and IEnumerable<T>.

至于您的更改，尽管 List 可以工作，但通过接口公开是一个不错的选择.接口定义了契约而不是实现.实施可能改变.例如，在某些情况下，实现可能是 HashSet.(顺便说一下，这是一种不仅可以用于实体框架的思维方式.面向对象的良好做法是针对接口而不是实现进行编程.实现可以并且将会改变.)

As for your change, exposing via the interface is a good choice, despite List<T> working. The interface defines the contract but not the implementation. The implementation could change. In some instances, perhaps the implementation could be a HashSet<T>, for example. (This is a mindset you could use for more than just Entity Framework, by the way. A good object-oriented practice is to program towards the interface and not the implementation. Implementations can and will change.)

这篇关于ICollection<T>与列表<T>在实体框架中的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！