我目前正在开发一个应用程序,它使用PRISM 4将其功能划分为不同的模块。
我注意到我的应用程序的Shell,它在其区域中保存模块的视图,在模块加载之前被加载并显示。
这意味着首先显示Shell,在相当长的一段时间之后(大约半秒),加载模块并将视图插入到Shell区域中。这是相当烦人的,因为用户在启动时看到的是一个空的shell,这不是很专业。
是否有任何方法可以检测所有模块何时已加载?我可以在引导程序中重写任何方法?
如果可以的话,我想隐藏Shell(或显示加载装饰器),直到所有模块都加载完毕。
可以在模块初始化后显示Shell视图:
protected override void InitializeShell()
{
Application.Current.MainWindow = (Window)Container.Resolve<ShellView>();
}
protected override void InitializeModules()
{
base.InitializeModules();
Application.Current.MainWindow.Show();
}
我找到了一个相对简单的解决办法。
我的应用程序有一个名为ShellHandler的类,它在引导程序中实例化,并在Unity容器中作为一个单例注册:
Container.RegisterType<IShellHandler, ShellHandler>(new ContainerControlledLifetimeManager());
我在我的ShellHandler中创建了一个方法,可以被模块用来标记自己加载:
/// <summary>
/// Method used to increment the number of modules loaded.
/// Once the number of modules loaded equals the number of modules registered in the catalog,
/// the shell displays the Login shell.
/// This prevents the scenario where the Shell is displayed at start-up with empty regions,
/// and then the regions are populated as the modules are loaded.
/// </summary>
public void FlagModuleAsLoaded()
{
NumberOfLoadedModules++;
if (NumberOfLoadedModules != ModuleCatalog.Modules.Count())
return;
// Display the Login shell.
DisplayShell(typeof(LoginShell), true);
}
最后,在所有模块都实现的ModuleBase类中,我创建了一个在初始化过程中调用的抽象方法:
/// <summary>
/// Method automatically called and used to register the module's views, types,
/// as well as initialize the module itself.
/// </summary>
public void Initialize()
{
// Views and types must be registered first.
RegisterViewsAndTypes();
// Now initialize the module.
InitializeModule();
// Flag the module as loaded.
FlagModuleAsLoaded();
}
public abstract void FlagModuleAsLoaded();
每个模块现在通过它们的构造函数解析ShellHandler单例实例:
public LoginModule(IUnityContainer container, IRegionManager regionManager, IShellHandler shellHandler)
: base(container, regionManager)
{
this.ShellHandler = shellHandler;
}
最后他们从ModuleBase实现抽象方法:
/// <summary>
/// Method used to alert the Shell Handler that a new module has been loaded.
/// Used by the Shell Handler to determine when all modules have been loaded
/// and the Login shell can be displayed.
/// </summary>
public override void FlagModuleAsLoaded()
{
ShellHandler.FlagModuleAsLoaded();
}