通用信息库，DI，聚集根 [英] Generic repository, DI, Aggregation Roots
问题描述
拥有一个像
public class Repository<T>
where T: Entity<T>
{
/*anything else*/
}
应每根agregation混凝土仓库像
should concrete repositories per agregation root like
class ProductRepository : Repository<Product>
{
}
class CategoryRepository : Repository<Category>
{
}
创建？
be created?
另外我怎么使用DI（ Ninject ）与通用实现仓库的。
Also how do I use DI (Ninject) with generic implementation of repository.
样品apreciated！
Samples are apreciated!
谢谢！
推荐答案
我看到了很多在这样的问题仿制药的滥用，虽然它并不一定是指你的问题（虽然这将有助于澄清），我想一次都在这里写一个总结。
I see a lot of misuse of generics in the questions in SO and while it does not necessarily refer to your question (although it will help to clarify), I think once for all write a summary here.
泛型是无类型行为的重用（差不多，因为你可以使用限制限制类型）。如果一个行为是由所有类型的共享（或者那些仅限于限制）您使用泛型。
Generics is a typeless reuse of the behaviour (almost, since you can limit the types using restrictions). If a behaviour is shared by all types (or those limited to restrictions) you use the generics.
不过，如果需要单独执行，然后使用实现每个泛型类型。仿制药没有帮助，并减少到装饰 - 对我来说是糟糕的设计。
However if implementation of each generic type needs to be individually implemented, then using generics does not help and is reduced to a decoration - and for me it is bad design.
好吧，让我们有一个例子：
OK, let's have an example:
interface IConverter<T1, T2>
{
T1 Convert(T2 t2);
}
这看起来像一个很好的仿制药（一种类型转换为另一种），但我必须实现的类型，不同的转换器，所有这样的组合。和 IConverter<苹果，橘子> 没有任何意义。因此，这里的仿制药是一种误导和坏的。
This looks like a good generics (converting one type to another), but I have to implement all such combinations of types as different converters. And a IConverter<Apple, Orange> does not make any sense. Hence generics here is misleading and BAD.
现在要回库。有关于这个具体问题（许多争议），文章数百但这个人我的看法：
Now going back to repositories. There are 100s of articles on this particular issue (lots of controversies) but this is personal my take:
通常不建议使用通用存储库。 然而，以我个人的经验，我用通用的存储库，以实现共同的东西（由基底回购来实现），然后使用单独的，如果有任何额外的：
Usually it is not recommended to use generic repositories. However, in my personal experience I use generic repository to implement common stuff (implemented by a base repo) and then use individual ones if there is any additional:
interface IRepository<T>
{
T GetById(int id);
IEnumerable<T> GetAll();
void Save(T t);
}
class BaseRepository<T> : IRepository<T>
{
... // implement common methods
}
interface IProductRepository : IRepository<T>
{
IEnumerable<T> GetTop5BestSellingProducts();
}
class ProductRepository : BaseRepository<T>, IProductRepository
{
... // implement important methods
}
注意
有些人认为库必须允许标准传递到存储库（ Eric Evans的DDD书），但我再做一次不觉得我不得不同意。我更喜欢在库（如 GetTopFiveBestSellingProducts 或 GetTopBestSellingProducts ），除非有这样的100S就像一个域显著声明。报告作者是病例只有1％
Some believe repository must allow for criteria to be passed to the repository (Eric Evans DDD book) but I again do not feel I have to agree to that. I prefer a domain-significant declaration on the repository (e.g. GetTopFiveBestSellingProducts or GetTopBestSellingProducts) unless there are 100s of such like in a report writer which is only 1% of cases.
第二个问题：
我不使用Ninject，但任何DI，这里是你怎么做。
I do not use Ninject but for any DI, here is how you do it
// PSEUDOCODE !!!
container.Register<IProductRepository , ProductRepository>();
根据DI框架，它可以略有不同。
depending on DI framework, it can be slightly different.
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