c# - WinForms 中的 MVP 导航

Question

一直在学习 MVP，并尝试在 WinForms 中使用它编写测试应用程序。我正在努力寻找一个关于如何在我的表单/ View 之间导航的很好解释的示例。例如，程序启动，我想显示一个登录对话框，如果登录成功则进入我的主视图。目前，我的 Main 方法看起来像这样:

static void Main()
{
   var loginView = Injector.Resolve<ILoginView>();
   if (loginView.DoLogin() != LoginResult.OK) return;
   var mainView = Injector.Resolve<IMainView>();
   Application.Run(mainView); // won't work as mainView isn't a form
}

Injector 对象只是 IoC 工具(当前为 StructureMap)的包装器。问题是，我读到过我不应该真的通过 Injector 手动创建实例，因为它们实际上应该通过构造函数注入(inject)来完成。

我在一定程度上做到了这一点，但在导航方面却没有做到。我想不出一种优雅的方式来表达我的观点，想知道这里是否有人可以对此有所启发？我已经阅读了一些关于应用程序 Controller 的内容，但没有找到一个示例来清楚地展示它。

Answer 1

关于导航问题:

I've managed to do this up to a point but not when it comes to navigation. I can't think of an elegant way of moving through my views and was wondering if anyone here might shed some light on this? I've read a little on application controllers but have not found an example to show it clearly.

下面是我使用过的结构的简化版本。请注意，调用 NavigateTo 方法时会自动调用设置和拆卸 Hook 。另外，+1 给@AlexBurtsev，因为他的回答暗示了这种非常相同的方法。

// Presenter can and should offer common services for the
// subclasses 
abstract class Presenter
{

   public void Display()
   {
      OnDisplay();
   }

   public void Dismiss()   
   {
      OnDismiss();
   }


   protected virtual OnDisplay() // hook for subclass
   {   
   }

   protected virtual OnDismiss() // hook for subclass
   {   
   }

   private NavigationManager _navMgr;

   internal NavigationMgr NavigationManager
   {   
      get
      {
         return _navMgr;
      }
      set
      {
         _navMgr = value;
      }

   }

}

// NavigationManager is used to transition (or navigate) 
// between views
class NavigationManager
{

   Presenter _current;

   // use this override if your Presenter are non-persistent (transient)
   public void NavigateTo(Type nextPresenterType, object args)
   {   
      Presenter nextPresenter = Activator.CreateInstance(nextPresenterType);   
      NavigateTo(nextPresenter);   
   }

   // use this override if your Presenter are persistent (long-lived)
   public void NavigateTo(Presenter nextPresenter, object args)
   {
      if (_current != null)
      {
         _current.Dismiss()
         _current.NavigationMgr = null;
         _current = null;
      }

      if (nextPresenter != null)
      {
         _current = nextPresenter;
         _current.NavigationMgr = this;
         _current.Display(args);
      }         
   }

}


class MainMenuPresenter : Presenter
{

   private IMainMenuView _mainMenuView = null;

   // OnDisplay is your startup hook
   protected override void OnDisplay()
   {
      // get your view from where ever (injection, etc)
      _mainMenuView = GetView();      

      // configure your view
      _mainMenuView.Title = GetMainTitleInCurrentLanguage();
      // etc      
      // etc

      // listen for relevent events from the view
      _mainMenuView.NewWorkOrderSelected += new EventHandler(MainMenuView_NewWorkOrderSelected);

      // display to the user
      _mainMenuView.Show();
   }

   protected override void OnDismiss()
   {
      // cleanup
      _mainMenuView.NewWorkOrderSelected -= new EventHandler(MainMenuView_NewWorkOrderSelected);
      _mainMenuView.Close();
      _mainMenuView = null;
   }

   // respond to the various view events
   private void MainMenuView_NewWorkOrderSelected(object src, EventArgs e)
   {
      // example of transitioning to a new view here...
      NavigationMgr.NavigateTo(NewWorkOrderPresenter, null);            
   }

}


class NewWorkOrderPresenter : Presenter
{

   protected override void OnDisplay()
   {
      // get the view, configure it, listen for its events, and show it
   }

   protected override void OnDismiss()
   {
      // unlisten for events and release the view
   }

}