c# – 在抽象工厂模式中使用IoC？

2023年5月25日 173次阅读

在Factory Pattern中使用IoC容器是不好的做法？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实现在它们的构造函数中有很多参数,并且每个对话框在实例化时必须有新的UnitOfWork.

这是我如何使用它：

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)
        {
            //...
        }
    }
}

最佳答案 您应该尽量避免将IoC容器注入工厂,而是查看您的IoC框架是否可以为您生成工厂.然而,这并不总是可行的,在那些情况下,我认为在工厂中使用容器是可以接受的,只要它永远不会逃脱.

我个人不会把容器放在一个服务中(如上所述),因为我觉得这个类现在有两个职责,注入框架已经转移到应用程序逻辑中.

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