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POBind to an attached behavior on a Storyboard
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  1. POBind to an attached behavior on a Storyboard
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    copied!<p>I have created an attached dependency property for Storyboards, with the intention of enabling me to call a method on my ViewModel when a Storyboard Completed event fires:</p> <pre><code>public static class StoryboardExtensions { public static ICommand GetCompletedCommand(DependencyObject target) { return (ICommand)target.GetValue(CompletedCommandProperty); } public static void SetCompletedCommand(DependencyObject target, ICommand value) { target.SetValue(CompletedCommandProperty, value); } public static readonly DependencyProperty CompletedCommandProperty = DependencyProperty.RegisterAttached( "CompletedCommand", typeof(ICommand), typeof(StoryboardExtensions), new FrameworkPropertyMetadata(null, OnCompletedCommandChanged)); static void OnCompletedCommandChanged(DependencyObject target, DependencyPropertyChangedEventArgs e) { Storyboard storyboard = target as Storyboard; if (storyboard == null) throw new InvalidOperationException("This behavior can be attached to Storyboard item only."); storyboard.Completed += new EventHandler(OnStoryboardCompleted); } static void OnStoryboardCompleted(object sender, EventArgs e) { Storyboard item = ... // snip ICommand command = GetCompletedCommand(item); command.Execute(null); } } </code></pre> <p>then I try to use it in XAML, with a Binding syntax:</p> <pre><code>&lt;Grid&gt; &lt;Grid.Resources&gt; &lt;Storyboard x:Key="myStoryboard" my:StoryboardExtensions.CompletedCommand="{Binding AnimationCompleted}"&gt; &lt;DoubleAnimation Storyboard.TargetProperty="Opacity" From="1" To="0" Duration="0:0:5" /&gt; &lt;/Storyboard&gt; &lt;Style x:Key="myStyle" TargetType="{x:Type Label}"&gt; &lt;Style.Triggers&gt; &lt;DataTrigger Binding="{Binding Path=QuestionState}" Value="Correct"&gt; &lt;DataTrigger.EnterActions&gt; &lt;BeginStoryboard Storyboard="{StaticResource myStoryboard}" /&gt; &lt;/DataTrigger.EnterActions&gt; &lt;/DataTrigger&gt; &lt;/Style.Triggers&gt; &lt;/Style&gt; &lt;/Grid.Resources&gt; &lt;Label x:Name="labelHello" Grid.Row="0" Style="{StaticResource myStyle}"&gt;Hello&lt;/Label&gt; &lt;/Grid&gt; </code></pre> <p>This fails with the following exception:</p> <blockquote> <p>System.Windows.Markup.XamlParseException occurred Message="Cannot convert the value in attribute 'Style' to object of type 'System.Windows.Style'. Cannot freeze this Storyboard timeline tree for use across threads. Error at object 'labelHello' in markup file 'TestWpfApp;component/window1.xaml' </p> </blockquote> <p>Is there any way to get the Binding syntax working with an attached ICommand property for a Storyboard?</p>
 

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