哪种类结构更可取? [英] Which class structure is more desirable?

问题描述

我不确定这两种模式"中哪一种最好.目前我使用选项 A(与提供者结合实现持久性)，但我现在偏向于 B，尤其是考虑到单元测试能够使用依赖注入"模型.

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();    
}

我想我要问的是，类公开返回其自身实例集合的静态方法是一种好的做法吗?

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?

似乎普遍认为选项 B 是更好的选择.看起来我前面有很多重构:S

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 ActiveRecord 模式(我假设 ClassA 中的 Save 方法将使用 ClassARepository ?)，这在某些情况下很好，但是，如果您有相当复杂的域模型，我不会使用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，我会使用这样的模型:

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 );
}

这意味着所有与持久化相关的逻辑都放在 ClassARepository 类中，而 ClassA 也没有直接访问存储库的权限.

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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