C# 如何在MEF中使用事件聚合器?
我正在运行最新的PRISM 4.2。不幸的是,文档中的事件聚合器教程是通过Unity而不是MEF驱动的。我不能让它在MEF下运行 App.xaml.csC# 如何在MEF中使用事件聚合器?,c#,.net,prism,mef,prism-4,C#,.net,Prism,Mef,Prism 4,我正在运行最新的PRISM 4.2。不幸的是,文档中的事件聚合器教程是通过Unity而不是MEF驱动的。我不能让它在MEF下运行 App.xaml.cs public partial class App : Application { [Import] public IEventAggregator eventAggregator; protected override void OnStartup(StartupEventArgs e
public partial class App : Application
{
[Import]
public IEventAggregator eventAggregator;
protected override void OnStartup(StartupEventArgs e)
{
base.OnStartup(e);
Bootstrapper bootstrapper = new Bootstrapper();
bootstrapper.Run();
}
}
public class Bootstrapper : MefBootstrapper
{
protected override DependencyObject CreateShell()
{
return new MainWindow();
}
protected override void InitializeShell()
{
base.InitializeShell();
App.Current.MainWindow = (Window)Shell;
App.Current.MainWindow.Show();
}
protected override void ConfigureAggregateCatalog()
{
base.ConfigureAggregateCatalog();
AggregateCatalog.Catalogs.Add(new AssemblyCatalog(this.GetType().Assembly));
}
protected override IModuleCatalog CreateModuleCatalog()
{
ModuleCatalog moduleCatalog = new ModuleCatalog();
return moduleCatalog;
}
}
public partial class MainWindow : Window, IView
{
public MainWindow()
{
InitializeComponent();
DataContext = new MainViewModel();
}
}
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = new MainViewModel();
//In this case the HandleAppExitEvent and the subscriber that deals with this event.
EventAggregatorHelper.Current.GetEvent<AppExitEvent>(). Subscribe(HandleAppExitEvent);
}
//note that this method should be public
public void HandleAppExitEvent(string mess)
{
if (!String.IsNullOrEmpty(mess))
{
//Do whatever you need to do here.
}
}
}
Bootstrapper.cs
public partial class App : Application
{
[Import]
public IEventAggregator eventAggregator;
protected override void OnStartup(StartupEventArgs e)
{
base.OnStartup(e);
Bootstrapper bootstrapper = new Bootstrapper();
bootstrapper.Run();
}
}
public class Bootstrapper : MefBootstrapper
{
protected override DependencyObject CreateShell()
{
return new MainWindow();
}
protected override void InitializeShell()
{
base.InitializeShell();
App.Current.MainWindow = (Window)Shell;
App.Current.MainWindow.Show();
}
protected override void ConfigureAggregateCatalog()
{
base.ConfigureAggregateCatalog();
AggregateCatalog.Catalogs.Add(new AssemblyCatalog(this.GetType().Assembly));
}
protected override IModuleCatalog CreateModuleCatalog()
{
ModuleCatalog moduleCatalog = new ModuleCatalog();
return moduleCatalog;
}
}
public partial class MainWindow : Window, IView
{
public MainWindow()
{
InitializeComponent();
DataContext = new MainViewModel();
}
}
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = new MainViewModel();
//In this case the HandleAppExitEvent and the subscriber that deals with this event.
EventAggregatorHelper.Current.GetEvent<AppExitEvent>(). Subscribe(HandleAppExitEvent);
}
//note that this method should be public
public void HandleAppExitEvent(string mess)
{
if (!String.IsNullOrEmpty(mess))
{
//Do whatever you need to do here.
}
}
}
MainWindow.xaml.cs
public partial class App : Application
{
[Import]
public IEventAggregator eventAggregator;
protected override void OnStartup(StartupEventArgs e)
{
base.OnStartup(e);
Bootstrapper bootstrapper = new Bootstrapper();
bootstrapper.Run();
}
}
public class Bootstrapper : MefBootstrapper
{
protected override DependencyObject CreateShell()
{
return new MainWindow();
}
protected override void InitializeShell()
{
base.InitializeShell();
App.Current.MainWindow = (Window)Shell;
App.Current.MainWindow.Show();
}
protected override void ConfigureAggregateCatalog()
{
base.ConfigureAggregateCatalog();
AggregateCatalog.Catalogs.Add(new AssemblyCatalog(this.GetType().Assembly));
}
protected override IModuleCatalog CreateModuleCatalog()
{
ModuleCatalog moduleCatalog = new ModuleCatalog();
return moduleCatalog;
}
}
public partial class MainWindow : Window, IView
{
public MainWindow()
{
InitializeComponent();
DataContext = new MainViewModel();
}
}
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = new MainViewModel();
//In this case the HandleAppExitEvent and the subscriber that deals with this event.
EventAggregatorHelper.Current.GetEvent<AppExitEvent>(). Subscribe(HandleAppExitEvent);
}
//note that this method should be public
public void HandleAppExitEvent(string mess)
{
if (!String.IsNullOrEmpty(mess))
{
//Do whatever you need to do here.
}
}
}
MainViewModel.cs:
[ModuleExport(typeof(MainViewModel))]
public class MainViewModel : BindableBase, IServiceCallback
{
[Import]
public IEventAggregator eventAggregator;
[ImportingConstructor]
public MainViewModel()
{
eventAggregator.GetEvent<AppExitEvent>().Publish("");
}
}
[ModuleExport(typeof(MainViewModel))]
公共类MainViewModel:BindableBase,IServiceCallback
{
[进口]
公共事件聚合器;
[导入构造函数]
公共主视图模型()
{
eventAggregator.GetEvent不再支持ComposeExportedValue
“System.ComponentModel.Composition.Hosting.CompositionContainer”没有
不包含“ComposeExportedValue”的定义且没有扩展
方法
在引导程序类中,请使用以下方法:
protected override void ConfigureContainer()
{
base.ConfigureContainer();
Container.ComposeExportedValue(new EventAggregator());
}
你应该看看这篇文章,因为它更详细地回答了你的第一个和第二个问题。
更新:
如果您按照下面的方式创建一个类,它将使您的导出与导入相匹配
public class EventAggProvider
{
[Export(typeof(IEventAggregator))]
public IEventAggregator eventAggregator { get { return new EventAggregator(); } }
}
EventAggregator
不依赖于MEF或Unity
它是由Martin Fowler创造的设计模式,它基于发布者-订阅者场景
尝试按照以下步骤操作
//这应该在您的基础结构层中
public static class EventAggregatorHelper
{
private static IEventAggregator _Current = new EventAggregator();
public static IEventAggregator Current
{
get
{
return _Current;
}
}
}
The HandleAppExitEvent is a class declared as shown below:
public class AppExitEvent : CompositePresentationEvent<String>
{
}
and the subscriber would be something like this:
公共静态类EventAggregatorHelper
{
私有静态IEventAggregator_Current=新事件聚合器();
公共静态励磁电流
{
得到
{
返回电流;
}
}
}
HandleAppExitEvent是一个声明如下所示的类:
公共类AppExitEvent:CompositePresentationEvent
{
}
用户应该是这样的:
在您的main窗口中.xaml.cs
public partial class App : Application
{
[Import]
public IEventAggregator eventAggregator;
protected override void OnStartup(StartupEventArgs e)
{
base.OnStartup(e);
Bootstrapper bootstrapper = new Bootstrapper();
bootstrapper.Run();
}
}
public class Bootstrapper : MefBootstrapper
{
protected override DependencyObject CreateShell()
{
return new MainWindow();
}
protected override void InitializeShell()
{
base.InitializeShell();
App.Current.MainWindow = (Window)Shell;
App.Current.MainWindow.Show();
}
protected override void ConfigureAggregateCatalog()
{
base.ConfigureAggregateCatalog();
AggregateCatalog.Catalogs.Add(new AssemblyCatalog(this.GetType().Assembly));
}
protected override IModuleCatalog CreateModuleCatalog()
{
ModuleCatalog moduleCatalog = new ModuleCatalog();
return moduleCatalog;
}
}
public partial class MainWindow : Window, IView
{
public MainWindow()
{
InitializeComponent();
DataContext = new MainViewModel();
}
}
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = new MainViewModel();
//In this case the HandleAppExitEvent and the subscriber that deals with this event.
EventAggregatorHelper.Current.GetEvent<AppExitEvent>(). Subscribe(HandleAppExitEvent);
}
//note that this method should be public
public void HandleAppExitEvent(string mess)
{
if (!String.IsNullOrEmpty(mess))
{
//Do whatever you need to do here.
}
}
}
公共部分类主窗口:窗口
{
公共主窗口()
{
初始化组件();
DataContext=新的MainViewModel();
//在本例中,HandleAppExitEvent和处理此事件的订阅服务器。
EventAggregatorHelper.Current.GetEvent().Subscribe(HandleAppExitEvent);
}
//请注意,此方法应该是公共的
公共无效HandleAppExitEvent(字符串混乱)
{
如果(!String.IsNullOrEmpty(mess))
{
//在这里你需要做什么就做什么。
}
}
}
解决方法是舒伯特在CodePlex上回答您的问题:
作为更深入的分析,在构造函数完成之前,属性上的导入属性不会被解析。这就是为什么如果此依赖项将用于构造函数实现,则需要通过构造函数将事件聚合器依赖项作为参数注入的原因
因此,如果要使用ViewModel构造函数上的EventAggregator依赖项,则应改为使用[ImportConstructor]属性,并通过将其作为参数检索,请求容器提供EventAggregator实例:
public class MainViewModel
{
private readonly IEventAggregator eventAggregator;
[ImportingConstructor]
public MainViewModel(IEventAggregator eventAggregator)
{
this.eventAggregator = eventAggregator;
this.eventAggregator.GetEvent<MyEvent>().Publish("");
}
}
public类主视图模型
{
私有只读IEventagor事件聚合器;
[导入构造函数]
公共主视图模型(IEventAggregator事件聚合器)
{
this.eventAggregator=eventAggregator;
此.eventAggregator.GetEvent().Publish(“”);
}
}
您可以在以下帖子中找到有关这两种导入替代方案的更多相关信息:
我希望这对您有所帮助,尊敬的。现在有点晚了,但是对于您希望在属性中注入EventAggregator的情况,还有一个解决方案。实现“iPartimportSSatifiedNotification”并在“OnImportSSatified”方法中使用EventAggregator
public class MainViewModel : BindableBase, IPartImportsSatisfiedNotification
{
[Import]
public IEventAggregator eventAggregator;
public void OnImportsSatisfied()
{
eventAggregator.GetEvent<AppExitEvent>().Publish("");
}
}
public类主视图模型:BindableBase、iPartimportsAssetFiedNotification
{
[进口]
公共事件聚合器;
公共无效OnImportsAssetized()
{
eventAggregator.GetEvent().Publish(“”);
}
}
你的文章在哪里?你确定你不是指配置聚合目录
而不是配置容器
?我以为前者处理应用程序中的MEF易耗件。你的文章与MEF和eventagregator@K.B阅读这篇文章,作者正在使用MEF,以及他使用它的方式这里回答了这两个问题。@TYY,我刚刚尝试了你的建议,它说ComposeExportedValue
找不到。在最新版本中,这些东西似乎已经改变了。我在3小时前写了那篇文章。我也无法让它工作。在StackOverflow中,答案应该有一个代码建议,而不是更多的文章。;)谢谢听我说。不过,你对我的答案有什么建议没有让你投赞成票吗?重点,也许是糟糕的问题解释?谢谢。完成。也接受了答案。;)