Caliburn与附加事件，目标失败

好吧，所以我试图将附加事件添加到控件。现在Caliburn不支持这个天真，但我似乎提供了一种解决方法used code from a different article。我基本上需要一种方法来添加这种代码this.AddHandler(RadDragAndDropManager.DragInfoEvent, new EventHandler<DragDropEventArgs>(OnDragInfo), true);，但caliburn不支持附加事件。这里是我的代码：Caliburn与附加事件，目标失败

<telerik:RadTreeView Height="250" Name="Root" Width="300" ItemTemplate="{StaticResource BusinessEntityTemplate}" IsDragDropEnabled="true" cal:Action.TargetWithoutContext="{Binding Source={x:Static RelativeSource.Self}}"> 
    <i:Interaction.Triggers> 
    <Helpers:RoutedEventTrigger RoutedEvent="{x:Static dragDrop:RadDragAndDropManager.DropQueryEvent}" IncludeHandledEvents="True"> 
     <cal:ActionMessage MethodName="OnDropQuery"> 
     <!--<cal:Parameter Value="$eventargs" />--> 
     </cal:ActionMessage> 
    </Helpers:RoutedEventTrigger> 
    </i:Interaction.Triggers> 
    </telerik:RadTreeViewItem>--> 
</telerik:RadTreeView>

RoutedEventTrigger定义如下：

public class RoutedEventTrigger : EventTriggerBase<DependencyObject> 
{ 
    RoutedEvent _routedEvent; 
    public RoutedEvent RoutedEvent 
    { 
     get { return _routedEvent; } 
     set { _routedEvent = value; } 
    } 
    bool _includeHandledEvents = false; 

    public bool IncludeHandledEvents 
    { 
     get { return _includeHandledEvents; } 
     set { _includeHandledEvents = value; } 
    } 

    public RoutedEventTrigger() { } 
    protected override void OnAttached() 
    { 
     Behavior behavior = base.AssociatedObject as Behavior; 
     FrameworkElement associatedElement = base.AssociatedObject as FrameworkElement; 
     if (behavior != null) 
     { 
      associatedElement = ((IAttachedObject)behavior).AssociatedObject as FrameworkElement; 
     } 
     if (associatedElement == null) 
     { 
      throw new ArgumentException("Routed Event trigger can only be associated to framework elements"); 
     } 
     if (RoutedEvent != null) 
     //{ associatedElement.AddHandler(RoutedEvent, new RoutedEventHandler(this.OnRoutedEvent)); } 
     { associatedElement.AddHandler(RoutedEvent, new RoutedEventHandler(this.OnRoutedEvent), this.IncludeHandledEvents); } 

    } 
    void OnRoutedEvent(object sender, RoutedEventArgs args) 
    { 
     base.OnEvent(args); 
    } 

    protected override string GetEventName() { return RoutedEvent.Name; } 
}

，并在我的ViewModel我只是有一个这样的处理程序：

public void OnDropQuery(object sender, DragDropQueryEventArgs e) {}

当我运行这个错误我得到是关于base.OnEvent(args);约No target found for method OnDropQuery.我很努力弄清楚为什么这不起作用。

来源

2013-01-15 macsux

发现问题，关于这个错误信息不是很明显。 viewmodel上的事件处理程序必须与xaml中的目标方法的定义相匹配。在这种情况下，这个问题被固定通过修改XAML如下：

   <cal:ActionMessage MethodName="OnDropQuery"> 
        <cal:Parameter Value="$source" /> 
        <cal:Parameter Value="$eventargs" /> 
       </cal:ActionMessage>

我也不得不删除cal:Action.TargetWithoutContext="{Binding Source={x:Static RelativeSource.Self}}"

来源

2013-01-15 18:35:26 macsux

Caliburn与附加事件，目标失败

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