Using Staticresouce in Visual State causes Blend Designer to break: "Invalid attribute value Unknow for property Background"

Question

I'm trying to change the Background of a Grid by using a Visual State and a Staticresouce as the value in the Setter of the Visual State. It works just fine at Runtime but the designer shows the following error (which doesn't help me a lot):

Exception: Der Text zu diesem Fehlercode wurde nicht gefunden. (unknown error)

Stacktrace: at Windows.UI.Xaml.Hosting.XamlUIPresenter.Render() at Microsoft.VisualStudio.DesignTools.WindowsXamlDesigner.Views.WindowsUIXamlImageHost.RenderWorker() at Microsoft.VisualStudio.DesignTools.WindowsXamlDesigner.Views.WindowsUIXamlImageHost.RenderScheduler.OnRender(Object object) at Microsoft.VisualStudio.DesignTools.WindowsXamlDesigner.Views.WindowsUIXamlImageHost.RenderScheduler.b__26_0(Object o) at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs) at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)

Invalid attribute value Unknown for property Background. InnerException: None

This is what I tried:

<Grid x:Name="grid">
    <VisualStateManager.VisualStateGroups>
        <VisualStateGroup x:Name="TestGroup">
             <VisualState x:Name="TestState">
                  <VisualState.Setters>
                       <Setter Target="grid.(Panel.Background)" Value="{StaticResource BackgroundBrush}" />
                  </VisualState.Setters>
             </VisualState>
        </VisualStateGroup>
    </VisualStateManager.VisualStateGroups>
</Grid>


<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">

    <SolidColorBrush x:Key="BackgroundBrush" Color="Black"/>
</ResourceDictionary>


<App>
    ...
    <App.Resources>
         <ResourceDictionary>
              <ResourceDictionary.MergedDictionaries>
                   <ResourceDictionary Source="Resources/Test.xaml"/>
              </ResourceDictionary.MergedDictionaries>
         </ResourceDictionary>
    </App.Resources>
</App>

Justin XL · Accepted Answer · 2015-08-17T13:08:18.363

0

The current Blend is really buggy so I am not surprised if you see errors like this.

One workaround is, reopen your page that contains this resource in Blend. You should see a dialog popping up (see below image). Then select your Test.xaml file from the Available dictionaries dropdown and hit OK.

By doing so blend will generate a DesignTimeResources.xaml file under your project Properties and it should eliminate the error on the designer.

However, I also noticed that your <ResourceDictionary.MergedDictionaries> isn't wrapped within a <ResourceDictionary>. Shouldn't it be something like this instread?

<App.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="Resources/Test.xaml" />
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
</App.Resources>

Update

This is indeed a Blend bug which even happens with built-in resources. To replicate, try building the project and then go to the States tab and select a VisualState, right after you will see the Blend Designer crashed. Note that I have Run project code in XAML Designer (if supported) turned off.

Currently the only way to remove the crash is to reopen the xaml file.

edited Aug 17 '15 at 13:08

answered Aug 17 '15 at 10:48

Justin XL

38,763
7
88
133

Thanks I'll give it a try. So this is not a mistake of mine but a bug in Blend? This would be great news because it's akward defining all those setters without the designer just by typing them in. The missing ResourceDictionary is just a copy-paste error, I removed all the unnecessary parts, sry. – Cort3vl Aug 17 '15 at 11:09
If it works, then it could be a Blend bug. I'm not exactly sure how you structure your files but the issue seems to be that Blend couldn't locate that *Test.xaml* resource dictionary file. However, I just tried to create a demo project and did exactly what you described, it worked fine. Blend didn't complain. – Justin XL Aug 17 '15 at 11:16
I added a screenshot of the error message. I even tried it with a build-in resource and still the same error. – Cort3vl Aug 17 '15 at 11:25
`BackgroundAltBrushMedium` is not a built-in resource is it? Try using another `ThemeResource` instead. – Justin XL Aug 17 '15 at 11:28
Added another screenshot, still the same error. I just picked BackgroundAltBrushMedium from the resources I could pick on the property window while editing the Visual State so I guess it is, I haven't defined a resource with this key. – Cort3vl Aug 17 '15 at 11:38
No, that's also wrong. You should be using a `Brush` instead of `Color`. – Justin XL Aug 17 '15 at 11:39
I'm sorry my bad. Now it should be right but the error's still there. – Cort3vl Aug 17 '15 at 11:45
I'd suggest you to try removing parts in your project to locate what the issue really is. Is it a new project? Is it a project that migrated from earlier version of WinRT? – Justin XL Aug 17 '15 at 11:46
I copied parts of an old WinRT project but the project itself was created a week ago using Visual Studio 2015 RTM. I'll create a fresh project and try it out. – Cort3vl Aug 17 '15 at 11:49
Yeah, what I also noticed is that in the new uwp, we have `` but you have ` – Justin XL Aug 17 '15 at 11:51
Another copy-paste mistake. So I've created a fresh new project. I've done nothing but adding a VisualState with the Setter from the screenshot above. After building the project and selecting the Visual State in the state window of blend the exact same error occured. – Cort3vl Aug 17 '15 at 11:59
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/87162/discussion-between-justin-xl-and-cort3vl). – Justin XL Aug 17 '15 at 12:00

Using Staticresouce in Visual State causes Blend Designer to break: "Invalid attribute value Unknow for property Background"

1 Answers1

Update