Visual studio 2013 Designer crashing on custom IBehavior - visual-studio-2013

Question

I want to use a custom IBehavior to be able to show/hide the StatusBar from XAML in a Universal app targeted at Windows Phone 8.1.
The code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Microsoft.Xaml.Interactivity;
using Windows.ApplicationModel;
using Windows.UI.ViewManagement;
using Windows.UI.Xaml;
namespace test.Behaviors
{
public class StatusBarBehavior : DependencyObject, IBehavior
{
public DependencyObject AssociatedObject { get; private set; }
public void Attach(DependencyObject associatedObject) { }
public void Detach() { }
public StatusBarBehavior()
{
}
public bool Show
{
get { return Convert.ToBoolean(GetValue(ShowProperty)); }
set { SetValue(ShowProperty, value); }
}
public static readonly DependencyProperty ShowProperty =
DependencyProperty.Register("Show",
typeof(object),
typeof(StatusBarBehavior),
new PropertyMetadata(null, OnIsVisibleChanged));
private static async void OnIsVisibleChanged(DependencyObject d,
DependencyPropertyChangedEventArgs e)
{
var statusBar = StatusBar.GetForCurrentView();
if (statusBar == null || e == null || e.NewValue == null || DesignMode.DesignModeEnabled)
return;
if (Convert.ToBoolean(e.NewValue))
await statusBar.ShowAsync();
else
await statusBar.HideAsync();
}
}
}
XAML:
<Page
x:Class="test.TestPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:test"
xmlns:behavior="using:test.Behaviors"
xmlns:i="using:Microsoft.Xaml.Interactivity"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<i:Interaction.Behaviors>
<behavior:StatusBarBehavior Show="False"/>
</i:Interaction.Behaviors>
<!-- page content -->
</Page>
The Behaviors SDK (12.0) has been added as a reference to the project.
Unfortunatly in Visual Studio 2013 (Community edition, Update 4), the design window for the page in question shows an error:
COMException: Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))
StackTrace: Empty
InnerException: None
However, the StatusBarBehavior works perfectly fine when I deploy the app on a device, no errors are thrown.
Is there a way to fix this error? Having the design window is quite necessary to preview the layout of the pages...

Answer 1

Changing the OnVisibleChanged event to
private static async void OnIsVisibleChanged(DependencyObject d,
DependencyPropertyChangedEventArgs e)
{
if (DesignMode.DesignModeEnabled) { return; }
var statusBar = StatusBar.GetForCurrentView();
if (statusBar == null || e == null || e.NewValue == null)
return;
if (Convert.ToBoolean(e.NewValue))
await statusBar.ShowAsync();
else
await statusBar.HideAsync();
}
fixes the issue. I assume StatusBar.GetForCurrentView() throws an error in the design view.