哪个阶级结构更可取？ [英] Which class structure is more desirable?

问题描述

我不知道其中的两个模式是最好的。目前我使用选项A（连同实现持久性的提供者），但我现在对犯错误B，特别是在单元测试中能够使用的依赖注入模式的光。

I'm not sure which of these two "patterns" is the best. Currently I use option A (in conjunction with a provider for implementing persistence), but I'm now erring towards B, especially in light of unit tests being able to use the "dependency injection" model.

选项A：

class ClassA
{
   ClassA() { }
   Save();
   static List<ClassA> GetClassAs();   
}

选项B：

class ClassA
{
   ClassA() { }
   Save();
}

class ClassARepository
{
    ClassARepository() { }
    List<ClassA> GetClassAs();    
}

我觉得我问的是，它是一类以暴露返回自己的实例集合静态方法好的做法呢？

I think what I'm asking is, is it good practice for a class to expose static methods that return collections of instances of itself?

有似乎是选项B是更好的选择的普遍共识。貌似我有很多重构提前：•

There seems to be a general consensus that Option B is the better choice. Looks like I have plenty of refactoring ahead :S

推荐答案

选项B看起来有点像的 ActiveRecord的模式（我假设在ClassA的保存方法将使用ClassARepository？），这是在某些情况不错，但是，如果你有相当复杂的域模型，我不会使用的ActiveRecord '模式。

Option B looks a bit like the ActiveRecord pattern (I Assume the Save method in ClassA will use the ClassARepository ? ), which is good in some situations, but, if you have rather complex domain-model, I wouldn't use the 'ActiveREcord' pattern.

相反，我会用这样的模式：

Instead, I would use such a model:

public class ClassA
{
   public int Id {get; private set;}
   public string Name {get; set;}
}

public class ClassARepository
{
    public ClassA Get( int id );

    public void Save( ClassA item );
}

这意味着所有相关的持续性逻辑放在ClassARepository类，ClassA的也有到仓库直接访问。

Which means that all persistence related logic is put in the ClassARepository class, and ClassA has also no direct access to the repository.

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