c# - WPF - MVVM - 谁负责新的 DataProvider 连接？

Question

我知道这可能是一个“编码风格”问题，但此时我真的很困惑。目前我正在尝试遵循 MVVM 模式(ViewModel、Repository、Controller 等)

但是谁应该发起与数据源的连接呢？尤其是当多个 Controller 需要一个事件连接时？

没有那么多可能性——要么每个 Controller 自己打开一个新连接，相应的 ViewModel 打开连接并将其传递给存储库，存储库又将其传递给它的 Controller ——或者连接更早地实例化(例如 StartUp.cs)。

我知道没有“完美”的解决方案，但我希望能得到一些启发，也许还有一个好的/最佳实践。

更新 1

示例代码:

namespace Question {
class ViewModel {

    Person.Person p;
    Department.Department d;

    Person.PersonRepository pR;
    Department.DepartmentRepository dR;

    // Here in the VM both classes (Person and Department) intersect - should I inject an instance of a "IDataProvider" from here into the Repositorys?
    // If so, I'd have to pass it to the repository which has to pass it to it's controller.
 }
}

namespace Question.Person {
class Person {
    // Person Model
}

class PersonRepository {
    // This class does whatever a repository does and delegates database query to it's controller
}

class PersonController {

    // Or should the Controller itself instantiate a new "IDataProvider" ?

    // This class needs a connection to the databse to execute querys
 }
}

namespace Question.Department {

class Department {
    // Department Model
}

class DepartmentRepository {
    // This class does whatever a repository does and delegates database query to it's controller
}

class DepartmentController {
    // This class needs a connection to the databse to execute querys
 }
}

Answer 1

我认为您混淆了 MVC 和 MVVM:

ViewModel 负责从模型中检索信息，使用从数据库中获取数据的存储库，您在这里不需要 Controller 。

 public ViewModel()
    {
       Person.PersonRepository pR;
       Department.DepartmentRepository dR;
     }

或者更好inject a repository interface进入您的 ViewModel 以获得干净、解耦和可测试的实现:

public ViewModel(IPersonRepository personRepo, IDepartmentRepository depRepo)
    {
       Person.PersonRepository pR = personRepo;
       Department.DepartmentRepository dR = depRepo;
     }