Caliburn笔记-Dependent Action(wpf框架)

   http://caliburn.codeplex.com/wikipage?title=Dependent%20Actions&referringTitle=Documentation

   这一部分功能也属于过滤器.再来看两个接口

FilterManager会在构造函数中,对实现该接口的Filter进行初始化

public interface IInitializable : IFilter{    /// <summary>    /// Initializes the filter.    /// </summary>    /// <param name="targetType">Type of the target.</param>    /// <param name="metadataContainer">The metadata container.</param>    /// <param name="serviceLocator">The serviceLocator.</param>    void Initialize(Type targetType, IMetadataContainer metadataContainer, IServiceLocator serviceLocator);}

 

public FilterManager(Type targetType, IMetadataContainer metadataContainer, IServiceLocator serviceLocator){…    filters.OfType<IInitializable>()        .Apply(x => x.Initialize(targetType, metadataContainer, serviceLocator));…
}

IHandlerAware用来实现对事件的监听

public interface IHandlerAware : IFilter{    /// <summary>    /// Makes the filter aware of the <see cref="IRoutedMessageHandler"/>.    /// </summary>    /// <param name="messageHandler">The message handler.</param>    void MakeAwareOf(IRoutedMessageHandler messageHandler);    /// <summary>    /// Makes the filter aware of the <see cref="IMessageTrigger"/>.    /// </summary>    /// <param name="messageHandler">The message handler.</param>    /// <param name="trigger">The trigger.</param>    void MakeAwareOf(IRoutedMessageHandler messageHandler, IMessageTrigger trigger);}

如DependenciesAttribute的实现,DependencyObserver对实现INotifyPropertyChanged的对象进行了监听.

public void MakeAwareOf(IRoutedMessageHandler messageHandler){    var notifier = messageHandler.Unwrap() as INotifyPropertyChanged;    if (notifier == null) return;    var helper = messageHandler.GetMetadata<DependencyObserver>();    if (helper != null) return;    helper = new DependencyObserver(messageHandler, notifier);    messageHandler.AddMetadata(helper);}

然后在wpf元素初始化后,再次调用,添加事件

public void MakeAwareOf(IRoutedMessageHandler messageHandler, IMessageTrigger trigger){    var helper = messageHandler.GetMetadata<DependencyObserver>();    if (helper == null) return;    if(trigger.Message.RelatesTo(_target))        helper.MakeAwareOf(trigger, _dependencies);}

DependencyObserver的MakeAwareOf.本质上海还是添加了MessageTrigger

public void MakeAwareOf(IMessageTrigger trigger, IEnumerable<string> dependencies){    foreach (var dependency in dependencies)    {        IList<IMessageTrigger> triggers;               if(!_triggersToNotify.TryGetValue(dependency, out triggers))        {            triggers = new List<IMessageTrigger>();            _triggersToNotify[dependency] = triggers;        }               if(!triggers.Contains(trigger))            triggers.Add(trigger);    }}