如何工作类的单位知道在提交调用的信息库？ [英] How does unit of work class know which repository to call on commit?
问题描述
* preface：我是pretty新的工作模式的单位*
我的目标是实现工作类的单位，将能够保持已在整个给定的交易改变了所有对象的轨道。一切，我读到工作格局的单位有它并排与存储库模式。所以这是我想使用的方法。
My goal is to implement a unit of work class that will be able to keep track of all objects that have been changed throughout a given transaction. Everything I read about the unit of work pattern has it side by side with the repository pattern. So this is the approach I'd like to use.
例如说，我创建了一个新的用户。在我的工作对象的单位，我有新创建的对象的列表，所以我加入我的新用户到这个列表。我的用户信息库有题为创建一个方法，它在用户和调用存储过程，将数据添加到数据库中。当我打电话提交我的工作单位，怎么会知道调用基于新的对象列表上库和方法？说它包含了用户对象和评论的对象。两者都是新建的，需要在提交补充道。我不确定如何做到这一点。
Say for example I create a new User. On my unit of work object, I have a list of newly created objects, so I add my new User to this list. My user repository has a method titled Create, which takes in a User and calls a stored procedure to add the data to the database. When I call commit on my unit of work, how will it know which repository and method to call based on the list of new objects? Say it contains a User object and a Comment object. Both are newly created and need to be added on commit. I'm uncertain how to accomplish this.
有人能解释这一点更好，甚至是一个小例子，如果可能的话？
Could somebody explain this a bit better and maybe even a small example if possible?
感谢。
推荐答案
一个解决这是使用控制反转的最常见的方式。
One of most common ways of solving this is using inversion of control.
例如，您已在类用户和评论，你已经实现了一个通用的存储库 IRepository＆LT; TDomainObject＆GT; 。这是获取用户或评论的储存库只是给TDomainObject参数：
For example, you've your classes User and Comment, and you've implemented a generic repository IRepository<TDomainObject>. That's getting a repository of User or Comment is just giving the TDomainObject parameter:
-
IRepository＆lt;使用者＆GT; -
IRepository＆LT;＆评论GT;
IRepository<User>IRepository<Comment>
后来你已经配置了谁的实施 IRepository＆lt;使用者＆GT; 和 IRepository＆LT;注释＆GT; ，因此，如果您使用像微软模式和放大器;实践通用服务定位器，而且我们在你的工作单位的commit方法的主体：
Later you've configured who's implementing IRepository<User> and IRepository<Comment>, so if you use something like Microsoft Pattern & Practices' Common Service Locator, and we're in the body of commit method in your unit of work:
foreach(DomainObject some in NewObjects)
{
((IRepository<DomainObject>)ServiceLocator.Current.GetInstance(Type.GetType(string.Format("NamespacesToGenericRepository.IRepository`1[[{0}]]", some.GetType().FullName)))).Add(some);
}
请注意 IRepository＆LT; TDomainObject＆GT; 有一个逆变 TDomainObject 的泛型参数，类型必须继承一个基域类型对象调用的的domainObject 的，它允许东西的上溯造型像 IRepository＆lt;使用者＆GT; 到 IRepository＆LT; domainObject的＆GT; 。
Note IRepository<TDomainObject> has a contravariant TDomainObject generic parameter which type must inherit a base type of Domain Object called DomainObject, which permits an upcast of something like IRepository<User> to IRepository<DomainObject>.
在换句话说，你的 IRepository＆LT; TDomainObject＆GT; 接口签名将是这样的：
In other words, your IRepository<TDomainObject> interface signature will look like this:
public interface IRepository<out TDomainObject>
where TDomainObject : DomainObject
这仅仅是一个有关如何实现定位的具体资料库总结和/或暗示的这样的 的域对象的工作能够管理任何专门的域对象的那些单位。
This is just a summary and/or hint about how to implement locating the concrete repository so an unit of work of domain objects can manage ones of any specialized domain object.
如果您想了解更多有关的控制反转的检查此Wikipedia文章：
If you want to learn more about inversion of control check this Wikipedia article:
- http://en.wikipedia.org/wiki/Inversion_of_control
和，因为我自己的经验，我想建议你温莎城堡作为的控制反转的选择的框架：
And, because of my own experience, I'd like to suggest you Castle Windsor as inversion of control framework of choice:
- http://www.castleproject.org/container/
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