使用StructureMap在模型 - 视图 - 展示器模式中进行Presenter注入

Question

我已经实现了我自己的模型视图演示者模式的副本(在Web客户端软件工厂的静脉中),所以我可以利用我自己的DI框架而不是绑定到WCSF的ObjectBuilder,我遇到了很多问题.我想出了几个方法来做到这一点,但没有一个特别让我开心.我想知道是否有其他人有其他想法.

解决方案#1a

使用HttpModule拦截context.PreRequestHandlerExecute来调用ObjectFactory.BuildUp(HttpContext.Current.Handler)

public partial class _Default : Page, IEmployeeView
{
    private EmployeePresenter _presenter;

    private EmployeePresenter Presenter
    {
        set
        {
            _presenter = value;
            _presenter.View = this;
        }
    }
}

解决方案#1b

在页面加载中调用buildup而不是使用HttpModule

public partial class _Default : Page, IEmployeeView
{
    private EmployeePresenter _presenter;

    private EmployeePresenter Presenter
    {
        set
        {
            _presenter = value;
            _presenter.View = this;
        }
    }

    protected void Page_Load(object sender, EventArgs e)
    {
        ObjectFactory.BuildUp(this);
    }
}

解决方案#1c

如果需要,通过Property访问presenter允许Getter to BuildUp.

public partial class _Default : Page, IEmployeeView
{
    private EmployeePresenter _presenter;

    public EmployeePresenter Presenter
    {
        get
        {
            if (_presenter == null)
            {
                ObjectFactory.BuildUp(this);
            }

            return _presenter;
        }
        set
        {
            _presenter = value;
            _presenter.View = this;
        }
    }
}

解决方案#2

public partial class _Default : Page, IEmployeeView
{
    private EmployeePresenter _presenter;

    private EmployeePresenter Presenter
    {
        get
        {
            if (_presenter == null)
            {
                _presenter = ObjectFactory.GetInstance<EmployeePresenter>();
                _presenter.View = this;
            }

            return _presenter;
        }
    }
}

解决方案#2b

public partial class _Default : Page, IEmployeeView
{
    private EmployeePresenter _presenter;

    private EmployeePresenter Presenter
    {
        get
        {
            if (_presenter == null)
            {
                Presenter = ObjectFactory.GetInstance<EmployeePresenter>();
            }

            return _presenter;
        }
        set
        {
            _presenter = value;
            _presenter.View = this;
        }
    }
}

编辑:添加解决方案1c,2b

Answer 1

我将使用解决方案#1b,并为所有页面创建一个图层超类型,以便更多地干预演示者初始化.像这样:

页码:

public partial class _Default : AbstractPage, IEmployeeView
{
    private EmployeePresenter presenter;

    private EmployeePresenter Presenter
    {
        set
        {
            presenter = value;
            presenter.View = this;
        }
    }
    protected override void Do_Load(object sender, EventArgs args)
    {
        //do "on load" stuff 
    }

}

摘要页码:

public abstract class AbstractPage : Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        ObjectFactory.BuildUp(this);
        this.Do_Load(sender,e); 
        //template method, to enable subclasses to mimic "Page_load" event

    }
    //Default Implementation (do nothing)
    protected virtual void Do_Load(object sender, EventArgs e){}
}

使用此解决方案,您只能在一个类中进行演示者初始化(由ObjectFactory创建),如果您以后需要对其进行修改,则可以轻松完成.

编辑:

Do_Load应该是抽象的还是虚拟的？

Template Method最初声明该方法应该是Abstract,以强制子类实现它,遵守超类契约.(参见维基百科"垄断"<"游戏"的例子).

另一方面,在这种特殊情况下,我们不希望强制用户类重新定义我们的方法,但给它机会这样做.如果你声明它是抽象的,许多类将被迫重新定义方法只是为了让它为空(这显然是代码味道).所以我们提供合理的默认值(什么都不做)并使方法成为虚拟的.