Behavior in Windows-Runtime Application

I have a set ScrollViewer

in my Windows Store app that should always have an action when they are double clicked (namely expand to full size). They are in different files, or I would probably just put this in the code for that file:

private void ScrollViewer_DoubleTapped(object sender, DoubleTappedRoutedEventArgs e)
{
    ScrollViewer sv = (ScrollViewer)sender;
    if (sv.HorizontalScrollBarVisibility == ScrollBarVisibility.Disabled)
    {
        sv.HorizontalScrollBarVisibility = ScrollBarVisibility.Hidden;
    }
    else
    {
        sv.HorizontalScrollBarVisibility = ScrollBarVisibility.Disabled;
    }
}

      

        
        
        
      

    

I was told to look at Behaviors, so I researched the behavior and with a few online tutorials I was able to come up with the following:

class ViewboxDoubleTap : DependencyObject, IBehavior
{
    public interface IBehavior
    {
        DependencyObject AssociatedObject { get; }
        void Attach(DependencyObject associatedObject);
        void Detach();
    }

    public void Attach(DependencyObject associatedObject)
    {
        if ((associatedObject != AssociatedObject) && !DesignMode.DesignModeEnabled)
        {
            if (AssociatedObject != null)
                throw new InvalidOperationException("Cannot attach behavior multiple times.");

            AssociatedObject = associatedObject;
            var fe = AssociatedObject as FrameworkElement;
            if (fe != null)
            {
                fe.AddHandler(UIElement.DoubleTappedEvent, new DoubleTappedEventHandler(ScrollViewer_DoubleTapped), true);
            }
        }
    }

    public void Detach()
    {
        var fe = AssociatedObject as FrameworkElement;
        if (fe != null)
        {
            fe.RemoveHandler(UIElement.DoubleTappedEvent, new DoubleTappedEventHandler(ScrollViewer_DoubleTapped));
        }

        AssociatedObject = null;
    }

    public DependencyObject AssociatedObject { get; private set; }

    private void ScrollViewer_DoubleTapped(object sender, DoubleTappedRoutedEventArgs e)
    {
        ScrollViewer sv = (ScrollViewer)sender;
        if (sv.HorizontalScrollBarVisibility == ScrollBarVisibility.Disabled)
        {
            sv.HorizontalScrollBarVisibility = ScrollBarVisibility.Hidden;
        }
        else
        {
            sv.HorizontalScrollBarVisibility = ScrollBarVisibility.Disabled;
        }
    }
}

      

        
        
        
      

    

Everything compiles nicely now, but I can't bind it to XAML:

XML namespaces:

xmlns:i="using:Microsoft.Xaml.Interactivity"
xmlns:core="using:Microsoft.Xaml.Interactions.Core"
xmlns:local="using:MyApp.Folder"
xmlns:global="using:MyApp"

      

        
        
        
      

    

Relevant code:

<ScrollViewer HorizontalAlignment="Left" VerticalScrollBarVisibility="Hidden" MaxZoomFactor="2" MinZoomFactor="1" MaxWidth="1067">

    <i:Interaction.Behaviors>
        <core:EventTriggerBehavior EventName="DoubleTapped">
            <global:ViewboxDoubleTap />
        </core:EventTriggerBehavior>
    </i:Interaction.Behaviors>

    <Border BorderBrush="Black" BorderThickness="1">
        <Image Source="MyImage.png"/>
    </Border>
</ScrollViewer>

      

        
        
        
      

    

When I try to go to this page nothing happens and when I debug it gives me this error message:

WinRT information: Cannot add instance of type 'LearnOneNote.ViewboxDoubleTap' to a collection of type 'Microsoft.Xaml.Interactivity.ActionCollection'. [Line: 25 Position: 30]

      

        
        
        
      

    

In addition, he tells me that ViewboxDoubleTap

he is not in namespace MyApp

, but when I type <global:

, he pulls it out himself; I don't know if this matters to the problem.

Any help would be appreciated.