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Windows Phone 7 中的导航框架是 Silverlight 中的精简版。您只能导航到 Uri 而不能传入视图。由于 NavigationService 与 View 绑定，人们如何使其适合 MVVM。例如：

public class ViewModel : IViewModel
{
    private IUnityContainer container;
    private IView view;

    public ViewModel(IUnityContainer container, IView view)
    {
        this.container = container;
        this.view = view;
    }

    public ICommand GoToNextPageCommand { get { ... } }

    public IView { get { return this.view; } }

    public void GoToNextPage()
    {
        // What do I put here.
    }
}

public class View : PhoneApplicationPage, IView
{
    ...

    public void SetModel(IViewModel model) { ... }
}

我正在使用 Unity IOC 容器。我必须先解析我的视图模型，然后使用 View 属性来获取视图，然后再显示它。但是使用 NavigationService，我必须传入一个视图 Uri。我没有办法先创建视图模型。有没有办法解决这个问题。

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4 回答 4

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而不是通过构造函数传递视图。您可以先通过 NavigationService 构造视图并将其传递给视图模型。像这样：

public class ViewModel : IViewModel
{
    private IUnityContainer container;
    private IView view;

    public ViewModel(IUnityContainer container)
    {
        this.container = container;
    }

    public ICommand GoToNextPageCommand { get { ... } }

    public IView 
    { 
        get { return this.view; } 
        set { this.view = value; this.view.SetModel(this); }
    }

    public void GoToNextPage()
    {
        // What do I put here.
    }
}

PhoneApplicationFrame frame = Application.Current.RootVisual;
bool success = frame.Navigate(new Uri("View Uri"));

if (success)
{
    // I'm not sure if the frame's Content property will give you the current view.
    IView view = (IView)frame.Content;
    IViewModel viewModel = this.unityContainer.Resolve<IViewModel>();
    viewModel.View = view;
}
于 2010-05-11T08:14:24.217 回答
2

如果您使用的是 Mvvm Light，您可以尝试：

Windows Phone 7 — 使用 MVVM Light Messaging 在页面之间导航

（参见类似帖子：Silverlight Navigation using Mvvm-light(oobe)+MEF?）

于 2010-07-28T15:28:23.927 回答
0

我的观点是视图模型应该在应用程序启动时创建和注册。通过将它放在根 DataContext 中，所有页面都将自动获得对它的引用，而无需任何代码隐藏或 IoC 技巧。

    // Code to execute when the application is launching (eg, from Start)
    // This code will not execute when the application is reactivated
    private void Application_Launching(object sender, LaunchingEventArgs e)
    {
        m_ViewModel = new PrimaryViewModel(RootFrame) ;
        RootFrame.DataContext = m_ViewModel;
    }

    // Code to execute when the application is activated (brought to foreground)
    // This code will not execute when the application is first launched
    private void Application_Activated(object sender, ActivatedEventArgs e)
    {
        m_ViewModel = new PrimaryViewModel(RootFrame) ;
        m_ViewModel.Activated(PhoneApplicationService.Current.State);
        RootFrame.DataContext = m_ViewModel;
    }
于 2012-01-09T23:35:49.040 回答
0

如果您使用的是 MVVM 架构，那么您可以在使用 Messenger 注册后传递 navigationPage。使用字符串（例如 PageName）变量创建模型类（例如 NavigateToPageMes​​sage）。您想将字符串从 homepage.xaml 传递给 newpage.xaml，然后在 Homepage viewmodel 中只需在您绑定的命令下发送这样的消息（比如 HomeNavigationCommand）

private void HomeNavigationCommandHandler()
        {
            Messenger.Default.Send(new NavigateToPageMessage {PageName = "newpage"});
        }

在新页面视图模型中，您应该像这样注册信使，

Messenger.Default.Register<NavigateToPageMessage>(this, (action) => ReceiveMessage(action));

 private object ReceiveMessage(NavigateToPageMessage action)
        {
            var page = string.Format("/Views/{0}.xaml", action.PageName);           
            NavigationService.Navigate(new System.Uri(page,System.UriKind.Relative));
            return null;
        }

//假设您的视图在视图文件夹中

于 2013-11-29T07:15:11.063 回答