mvvm和structuremap的使用

另一个选择…

看看这个LessonViewModel。它只取决于学生和老师,对家长或任何其他儿童对象一无所知。

public class LessonViewModel
{
    private IPupilsFactory _pupilsFactory;
    private ITeachersFactory _teachersFactory;

    public LessonViewModel(IPupilsFactory pupilsFactory, ITeachersFactory teachersFactory)
    {
        _pupilsFactory = pupilsFactory;
        _teachersFactory = teachersFactory;
    }

    public string Name { get; set; }
    public List<string> PupilNames { get; set; }
    public string TeacherName { get; set; }

    public PupilViewModel GetPupil(string name) 
    {
        return _pupilsFactory.Create(name);
    }

    public TeacherViewModel GetTeacher()
    {
        return _teachersFactory.Create(TeacherName);
    }
}

课程工厂包含所有必需的依赖项,但它也不了解pupilparents。

public interface ILessonsFactory
{
    LessonViewModel Create(string name);
}

public class LessonsFactory : ILessonsFactory
{
    private ILessonsRepository _lessonsRepository;
    private IPupilsFactory _pupilsFactory;
    private ITeachersFactory _teachersFactory;

    public LessonsFactory(ILessonsRepository lessonsRepository, IPupilsFactory pupilsFactory, ITeachersFactory teachersFactory)
    {
        _lessonsRepository = lessonsRepository;
        _pupilsFactory = pupilsFactory;
        _teachersFactory = teachersFactory;
    }

    public LessonViewModel Create(string name)
    {
        Lesson lesson = _lessonsRepository.Read(name);

        return new LessonViewModel(_pupilsFactory, _teachersFactory) {
            Name = lesson.Name,
            PupilNames = lesson.PupilNames,
            TeacherName = lesson.TeacherName
        };
    }
}

使用依赖注入的好处是,如果schoolsviewmodel本身不需要知道teachersrepository,那么它甚至不需要在构造函数中引用它。尽管家长对此一无所知,但孩子的viewmodel仍然能够处理teachersrepository。这可以防止父视图模型被它并不真正需要的依赖项污染。

也许我没有看到这里的大局?你不能用structuremap和它的所有基础来帮你处理这些肮脏的工作吗?您可以使用structuremap的构造函数注入来处理所有这些工作。通过连接一个接口以及它和它的子接口依赖于structuremap的所有接口,并将各种依赖接口放入需要它们的各种对象的构造函数中……当实例化依赖于对象2的对象1时,对象2又依赖于对象3……structuremap将把一切都搞定。

也许我遗漏了什么?