【Prism】MEF版Commanding

引言

接下来的是Commanding Demo的改造.

DelegateCommand

   WPF本身提供了一个RoutedCommand,然而没什么卵用.在Prism框架中提供了个更人性化的ICommand的实现--DelegateCommand,如下

public class ArticleViewModel : NotificationObject
{
    private readonly ICommand showArticleListCommand;

    public ArticleViewModel(INewsFeedService newsFeedService,
                            IRegionManager regionManager,
                            IEventAggregator eventAggregator)
    {
        this.showArticleListCommand = new DelegateCommand(this.ShowArticleList);
    }

    public ICommand ShowArticleListCommand
    {
        get { return this.showArticleListCommand; }
    }
}

CompositeCommand

CompositeCommand是Prism提供的一个组合式命令实现.它可以在子命令都可用的情况下同时执行多个子命令.应用情况不是很多,但是可以了解一下.如下

public class MyViewModel : NotificationObject
{
    private readonly CompositeCommand saveAllCommand;

    public ArticleViewModel(INewsFeedService newsFeedService,
                            IRegionManager regionManager,
                            IEventAggregator eventAggregator)
    {
        this.saveAllCommand = new CompositeCommand();
        this.saveAllCommand.RegisterCommand(new SaveProductsCommand());
        this.saveAllCommand.RegisterCommand(new SaveOrdersCommand());
    }

    public ICommand SaveAllCommand
    {
        get { return this.saveAllCommand; }
    }
}

示例源码

http://pan.baidu.com/s/1sjuWkod

小结

更多的Commandi用法可以在官方文档Prism 4.0的Chapter 9中查阅.