c# - 在抽象工厂模式中使用 IoC？

Question

在工厂模式中使用 IoC 容器是一种不好的做法吗？例如:

public interface IDialogService
{
    void RegisterView<TView, TViewModel>(string viewName) 
        where TViewModel : IDialogViewModel
        where TView : Window;

    bool? ShowDialog(string viewName, IDialogViewModel viewModel);
    // factory method:
    TViewModel CreateDialogViewModel<TViewModel>(string name) where TViewModel : IDialogViewModel;
}

public class DialogService : IDialogService
{
    private readonly IUnityContainer _container;
    public DialogService(IUnityContainer container)
    {
        _container = container;
    }

    #region IDialogService Members

    public void RegisterView<TView, TViewModel>()
        where TView : Window
        where TViewModel : IDialogViewModel
    {
        RegisterView<TView, TViewModel>("");
    }

    public void RegisterView<TView, TViewModel>(string viewName)
        where TView : Window
        where TViewModel : IDialogViewModel
    {
        if (!_container.IsRegistered<TViewModel>())
            _container.RegisterType<TViewModel>();

        if (string.IsNullOrEmpty(viewName))
        {
            viewName = typeof(TView).Name;
        }
        _container.RegisterType<Window, TView>(viewName);
    }

    public bool? ShowDialog(string viewName, IDialogViewModel viewModel)
    {
        var view = _container.Resolve<Window>(viewName);
        view.DataContext = viewModel;
        view.Owner = Application.Current.MainWindow;
        return view.ShowDialog();
    }
    // factory method:
    public TViewModel CreateDialogViewModel<TViewModel>(string name) where TViewModel : IDialogViewModel
    {
        return _container.Resolve<TViewModel>(name);
    }

    #endregion
}

我创建工厂方法的原因是因为我的一些 IDialogViewModel 实现在其构造函数中有很多参数，而且每个对话框在实例化时都必须有新的 UnitOfWork。

下面是我的使用方法:

public class PeopleMainViewModel : NotificationObject, ...
{
    private readonly IDialogService _dialogService = null;
    public PeopleMainViewModel(IDialogService dialogService)
    {
        _dialogService = dialogService;
    }

    // this method executes by a command.
    public void AddPerson()
    {
        // here is factory method usage. each time PersonDialogViewModel instantiates, a new Unit of work will be created.
        var viewModel = _dialogService.CreateDialogViewModel<PersonDialogViewModel>();

        // this shows person dialog window to user...
        var result = _dialogService.ShowDialog("PersonWindow", viewModel);
        if(result == true)
        {
            //...
        }
    }
}

Answer 1

您应该尽量避免将 IoC 容器注入(inject)工厂，而是查看您的 IoC 框架是否可以为您生成工厂。然而，这并不总是可能的，在这些情况下，我认为在工厂中使用容器是可以接受的，只要它永远不会逃逸。

就我个人而言，我不会将容器放在服务中(如上例所示)，因为在我看来类现在有两个职责并且注入(inject)框架已经逃逸到应用程序逻辑中。