我的Shell/MainWindow的ViewModel(通过AutoWireViewModel="True"
设置)请求一个依赖项,该依赖项在启动时使用ConfigurationModuleCatalog加载在模块中。
因为Shell是在模块之前初始化的,所以DI容器显然无法解决这个问题,所以应用程序会崩溃。
public class MainWindowViewModel : BindableBase
{
// Cannot resolve IService
public MainWindowViewModel(IService service)
{
}
}
我已经尝试了这篇文章的两种方法,但都不起作用。
我试过了:
public interface IShellService
{
int NumberOfLoadedModules { get; }
void FlagModuleAsLoaded();
}
public class ShellService : IShellService
{
private readonly IModuleCatalog _moduleCatalog;
public ShellService(IModuleCatalog moduleCatalog)
{
_moduleCatalog = moduleCatalog;
}
public int NumberOfLoadedModules { get; private set; }
public void FlagModuleAsLoaded()
{
NumberOfLoadedModules++;
if (NumberOfLoadedModules != _moduleCatalog.Modules.Count())
return;
InitializeShell();
}
private static void InitializeShell()
{
Application.Current.MainWindow.Show();
}
}
internal class Bootstrapper : UnityBootstrapper
{
protected override DependencyObject CreateShell()
{
return null;
}
protected override void InitializeShell()
{
}
protected override void ConfigureContainer()
{
base.ConfigureContainer();
Container.RegisterInstance<IShellService>(new ShellService(ModuleCatalog), new ContainerControlledLifetimeManager());
}
protected override IModuleCatalog CreateModuleCatalog()
{
return new ConfigurationModuleCatalog();
}
}
使用
public abstract class ModuleBase : IModule
{
private readonly IShellService _shellService;
protected ModuleBase(IShellService shellService)
{
_shellService = shellService;
}
public void Initialize()
{
InitializeInternal();
FlagAsLoaded();
}
public abstract void InitializeInternal();
public void FlagAsLoaded()
{
_shellService.FlagModuleAsLoaded();
}
}
public class FooModule : ModuleBase
{
IUnityContainer _container;
public MusicUIModule(IUnityContainer container, IShellService shellService) : base(shellService)
{
_container = container;
}
public override void InitializeInternal()
{
_container.RegisterType<IService, Service>();
}
}
它开始计数模块,然后应用程序崩溃,因为同样的原因。
如果上面的方法不适合我的目的,如何解决这个问题?
谢谢!
我尝试实现Haukinger的建议,并这样做了,工作得很好:
// Factory --------------------------------------------------------
public interface IDependencyFactory
{
IService GetService();
}
public class DependencyFactory : IDependencyFactory
{
private readonly IUnityContainer _container;
public DependencyFactory(IUnityContainer container)
{
_container = container;
}
public IService GetService()
{
return _container.Resolve<IService>();
}
}
// PubSubEvent ------------------------------------------------------
public class AllModulesLoaded : PubSubEvent
{
}
// Bootstrapper -----------------------------------------------------
internal class Bootstrapper : UnityBootstrapper
{
protected override DependencyObject CreateShell()
{
return Container.Resolve<MainWindow>();
}
protected override void InitializeShell()
{
Application.Current.MainWindow.Show();
}
protected override void InitializeModules()
{
base.InitializeModules();
// Publishing event to tell subscribers that the modules are loaded
var eventAggregator = Container.Resolve<IEventAggregator>();
eventAggregator?.GetEvent<AllModulesLoaded>().Publish();
}
protected override void ConfigureContainer()
{
base.ConfigureContainer();
// ...
Container.RegisterType<IDependencyFactory, DependencyFactory>();
}
protected override IModuleCatalog CreateModuleCatalog()
{
return new ConfigurationModuleCatalog();
}
}
// ViewModel ---------------------------------------------------------
public class MainWindowViewModel : BindableBase
{
private IService _service;
private readonly IEventAggregator _eventAggregator;
private readonly IDependencyFactory _dependencyFactory;
public MainWindowViewModel(IEventAggregator eventAggregator, IDependencyFactory dependencyFactory)
{
_eventAggregator = eventAggregator;
_dependencyFactory = dependencyFactory;
_eventAggregator.GetEvent<AllModulesLoaded>().Subscribe(OnAllModulesLoaded);
}
private void OnAllModulesLoaded()
{
var service = _dependencyFactory.GetService();
if (service != null)
_service = service ;
_eventAggregator.GetEvent<AllModulesLoaded>().Unsubscribe(OnAllModulesLoaded);
}
}
我会隐藏在工厂/提供商后面的shell依赖,然后在最后一个模块加载时创建/获取它。您的shell的视图模型订阅了一个AllModulesLoaded
事件,当base.InitializeModules
返回以获得依赖可用的通知时,该事件从您的引导程序的InitializeModules
触发。或者工厂/提供者订阅事件,然后shell轮询它,这取决于你想如何使用依赖项。