问两次创建棱镜/WPF视图/视图模型

EN

public partial class App : PrismApplication
{
    private ILoggerFactory loggerFactory;
    private TaskbarIcon _taskbarIcon;

    protected override Window CreateShell()
    {
        // Register an instance of the Window (used by the dialog service to get a handle on the window when displaying dialogs)
        Container.GetContainer().RegisterInstance(typeof(Window), "MainWindow", Container.Resolve<MainWindow>(), new ContainerControlledLifetimeManager());

        return Container.Resolve<MainWindow>();
    }

    protected override void OnInitialized()
    {
        base.OnInitialized();

        // Create the links to each module for the banner view to display
        var menuService = Container.Resolve<IMenuService>();
        var regionManager = Container.Resolve<IRegionManager>();

        menuService.AddItem("Home", "Home", () => regionManager.RequestNavigate("MainRegion", "HomeMainView"));
        menuService.AddItem("Messaging", "Messaging", () => regionManager.RequestNavigate("MainRegion", "MessagingMainView"));
        menuService.AddItem("Charts", "Charts", () => regionManager.RequestNavigate("MainRegion", "ChartsMainView"));
        menuService.AddItem("Admin", "Admin", () => regionManager.RequestNavigate("MainRegion", "AdminMainView"));

        // Register banner view with region manager and display it
        regionManager.RegisterViewWithRegion("BannerRegion", typeof(BannerView));

        // Load the desired module into the main window on start up
        Container.Resolve<IRegionManager>().RequestNavigate("MainRegion", "HomeMainView");
    }

    protected override void RegisterTypes(IContainerRegistry containerRegistry)
    {
        var container = this.ConfigureLogging(containerRegistry);

        // Register types 
        container.RegisterInstance<IDbConnectionFactory>(
            new SqlConnectionFactory(
                ConfigurationManager.ConnectionStrings["Messaging"].ConnectionString,
                loggerFactory));            

        /************************************************************/
        // TODO: Not sure if need singletons or not - to test......
        /************************************************************/
        containerRegistry.RegisterSingleton<IMetroMessageDisplayService, MetroMessageDisplayService>();
        containerRegistry.RegisterSingleton<IUserService, UserService>();
        containerRegistry.RegisterSingleton<IUserStore, UserStore>();
        containerRegistry.RegisterSingleton<IMenuService, MenuService>();
        containerRegistry.Register<ICustomerService, CustomerService>();
        containerRegistry.Register<INotifyIconService, NotifyIconService>();
        containerRegistry.RegisterDialog<DefaultDialog, DefaultDialogViewModel>("Default");
        containerRegistry.RegisterDialog<HtmlDialog, HtmlDialogViewModel>("Html");

        // Get the current user's details - prevent a deadlock in the way we use Task.Run(...).Result
        // Then add to container as we will be injecting into VMs
        var clientUser = Task.Run(GetCurrentUserDetails).Result;

        containerRegistry.RegisterInstance(clientUser);
        containerRegistry.RegisterSingleton<IClientUser, ClientUser>();

        // Add the task bar icon
        _taskbarIcon = (TaskbarIcon)FindResource("NotifyIcon");
        containerRegistry.RegisterInstance(_taskbarIcon);

        // Create a logger instance
        var logger = loggerFactory.CreateLogger<App>();

        logger.LogDebug("Finished registering types in App.xaml.cs");
    }

    private async Task<ClientUser> GetCurrentUserDetails()
    {
        var userService = Container.Resolve<IUserService>();
        var data = await userService.GetClientUsersAsync(ConfigurationManager.AppSettings.Get("TempUserName")).ConfigureAwait(true);

        if (!data.Any())
        {
            // log unable to load user from database then return as no point in loading messages for a user that cannot be found!!
            return null;
        }

        return data.FirstOrDefault();
    }

    protected override IModuleCatalog CreateModuleCatalog()
    {
        // We are returning a type that reads the modules from the config file.
        return new ConfigurationModuleCatalog();
    }

    protected override void OnExit(ExitEventArgs e)
    {
        // The icon would clean up automatically, but this is cleaner
        _taskbarIcon.Dispose();

        base.OnExit(e);
    }

    private IUnityContainer ConfigureLogging(IContainerRegistry containerRegistry)
    {
        // Configure logging - Needed Unity.Microsoft.Logging package 
        // see https://github.com/unitycontainer/microsoft-logging and https://github.com/unitycontainer/examples/tree/master/src/Logging/Microsoft.Logging
        var serilogLogger = new LoggerConfiguration()
            .ReadFrom.AppSettings()
            .CreateLogger();

        this.loggerFactory = new LoggerFactory().AddSerilog(serilogLogger);

        var container = containerRegistry.GetContainer();
        container.AddExtension(new LoggingExtension(loggerFactory));

        return container;
    }
}

public class MessagingModule : IModule
{
    public void OnInitialized(IContainerProvider containerProvider)
    {
        // Register main view with region manager
        var regionManager = containerProvider.Resolve<IRegionManager>();
        regionManager.RegisterViewWithRegion("MainRegion", typeof(MessagingMainView));
    }

    public void RegisterTypes(IContainerRegistry containerRegistry)
    {
        containerRegistry.RegisterSingleton<IMessageStore, MessageStore>();
        containerRegistry.RegisterSingleton<IMessageService, MessageService>();
        containerRegistry.RegisterSingleton<IChatService, ChatService>();
        containerRegistry.RegisterSingleton<IFileDialogService, FileDialogService>();
        containerRegistry.RegisterDialog<InboxMessageView, InboxMessageViewModel>("HtmlMessage");

        // Here we are loading the config/settings from the app.config for this module so we
        // can register a ChatServiceConfiguration type as it is injected into ChatService
        var filename = Assembly.GetExecutingAssembly().Location;

        var configuration = ConfigurationManager.OpenExeConfiguration(filename);

        if (configuration != null)
        {
            var hubUrl = configuration.AppSettings.Settings["HubUrl"].Value;

            if (string.IsNullOrEmpty(hubUrl))
            {
                throw new ArgumentException("The HubUrl app setting cannot ne null or whitespace.");
            }

            containerRegistry.RegisterInstance(new ChatServiceConfiguration(hubUrl));
            containerRegistry.RegisterSingleton<IChatServiceConfiguration, ChatServiceConfiguration>();
        }
    }
}

<UserControl x:Class="Ascensos.Wpf.Modules.Messaging.Views.MessagingMainView"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:Controls="http://metro.mahapps.com/winfx/xaml/controls"
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
         xmlns:iconPacks="http://metro.mahapps.com/winfx/xaml/iconpacks"
         xmlns:materialDesign="http://materialdesigninxaml.net/winfx/xaml/themes"
         xmlns:materialDesignConverters="clr-namespace:MaterialDesignThemes.Wpf.Converters;assembly=MaterialDesignThemes.Wpf"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
         xmlns:views="clr-namespace:Ascensos.Wpf.Modules.Messaging.Views"
         xmlns:helpers="clr-namespace:Ascensos.Wpf.Modules.Messaging.Helpers"
         xmlns:prism="http://prismlibrary.com/"
         prism:ViewModelLocator.AutoWireViewModel="True"
         d:DesignHeight="300"
         d:DesignWidth="400"
         mc:Ignorable="d">

</UserControl>

public sealed partial class MessagingMainView : UserControl
{
    public MessagingMainView()
    {
        this.InitializeComponent();
    }
}

public sealed class MessagingMainViewModel
{
    public MessagingMainViewModel()
    {            
    }
}