Prism应用开发（八）——松耦合组件之间通信

一、Commands

创建一个全局的command，该command将会在各个组件之间共享。

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1. public static class GlobalCommands  
2. {  
3. public static CompositeCommand MyCompositeCommand = new CompositeCommand();  
4. }  

public static class GlobalCommands{public static CompositeCommand MyCompositeCommand = new CompositeCommand();}

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1. GlobalCommands.MyCompositeCommand.RegisterCommand(command1);  
2. GlobalCommands.MyCompositeCommand.RegisterCommand(command2);  

GlobalCommands.MyCompositeCommand.RegisterCommand(command1);GlobalCommands.MyCompositeCommand.RegisterCommand(command2);

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1. <Button Name="MyCompositeCommandButton" Command="{x:Static  
2. local:GlobalCommands.MyCompositeCommand}">Execute My Composite Command </Button>  

<Button Name="MyCompositeCommandButton" Command="{x:Staticlocal:GlobalCommands.MyCompositeCommand}">Execute My Composite Command </Button>

二、Shared Service

module之间可以通过Shared Service相互通信而不用直接引用另一个module。

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1. protected void RegisterViewsAndServices()  
2. {  
3. _container.RegisterType<IMarketFeedService, MarketFeedService>(new  
4. ContainerControlledLifetimeManager());  
5. //...  
6. }  

protected void RegisterViewsAndServices(){_container.RegisterType<IMarketFeedService, MarketFeedService>(newContainerControlledLifetimeManager());//...}

三、Event Aggregation

Prism提供了为松耦合组件之间通信提供了事件的机制。这个机制基于event aggregator service。允许发布和订阅事件而不用使得各个module引用对方。

下面的代码用户创建，发布和订阅事件

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1. public class TickerSymbolSelectedEvent : CompositePresentationEvent<string>{}  

public class TickerSymbolSelectedEvent : CompositePresentationEvent<string>{}

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1. this.eventAggregator.GetEvent<TickerSymbolSelectedEvent>().Publish("STOCK0");  

this.eventAggregator.GetEvent<TickerSymbolSelectedEvent>().Publish("STOCK0");

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1. public void Run()  
2. {  
3. ...  
4. this.eventAggregator.GetEvent<TickerSymbolSelectedEvent>().Subscribe(ShowNews,  
5. ThreadOption.UIThread);  
6. );  
7. }  
8. public void ShowNews(string companySymbol)  
9. {  
10. this.articlePresentationModel.SetTickerSymbol(companySymbol);  
11. }  

public void Run(){...this.eventAggregator.GetEvent<TickerSymbolSelectedEvent>().Subscribe(ShowNews,ThreadOption.UIThread););}public void ShowNews(string companySymbol){this.articlePresentationModel.SetTickerSymbol(companySymbol);}

subscribe还提供了用于过滤的参数，例如：

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1. FundAddedEvent fundAddedEvent = this.eventAggregator.GetEvent<FundAddedEvent>();  
2. fundAddedEvent.Subscribe(FundAddedEventHandler, ThreadOption.UIThread, false,  
3. fundOrder => fundOrder.CustomerId == this.customerId);