MainPage.xaml throws an error while loading designer.

Question

Hello,

I am new to WIndows store app development.

I am creating a sample windows store App using VC++ UAP using Visual Studio 2015 CTP5. 

MainPage.xaml throws an error while loading the designer:

"The element [Grid] could not be displayed because of a problem with WIndows..UI.Xaml.Control.Grid"

Exception:

NullReferenceException: Object reference not set to an instance of an object.

at Microsoft.VisualStudio.DesignTools.WindowsXamlDesigner.WindowsStoreXamlPlatform.get_ThemeResources()
   at Microsoft.VisualStudio.DesignTools.Platform.InstanceBuilders.ClrObjectInstanceBuilder.FindInstantiatedResource(IInstanceBuilderContext context, ViewNode viewNode, DocumentNode documentNode, DocumentNode keyNode)
   at Microsoft.VisualStudio.DesignTools.Platform.InstanceBuilders.ClrObjectInstanceBuilder.UpdatePropertyOrChildValue(IInstanceBuilderContext context, ViewNode viewNode, IProperty propertyKey, Int32 childIndex, DocumentNodeChangeAction action, DocumentNode valueNode, ViewNode& childViewNode, IInstanceBuilder& valueBuilder, Boolean& isNewInstance)
   at Microsoft.VisualStudio.DesignTools.Platform.InstanceBuilders.ClrObjectInstanceBuilder.UpdateProperty(IInstanceBuilderContext context, ViewNode viewNode, IProperty propertyKey, DocumentNode valueNode)
   at Microsoft.VisualStudio.DesignTools.Platform.InstanceBuilders.DependencyObjectInstanceBuilderBase`1.UpdateProperty(IInstanceBuilderContext context, ViewNode viewNode, IProperty propertyKey, DocumentNode valueNode)
   at Microsoft.VisualStudio.DesignTools.WindowsXamlDesigner.InstanceBuilders.FrameworkElementInstanceBuilder.UpdateProperty(IInstanceBuilderContext context, ViewNode viewNode, IProperty propertyKey, DocumentNode valueNode)
   at Microsoft.VisualStudio.DesignTools.Platform.InstanceBuilders.ClrObjectInstanceBuilder.InstantiateProperties(IInstanceBuilderContext context, ViewNode viewNode, DocumentCompositeNode compositeNode)
   at Microsoft.VisualStudio.DesignTools.Platform.InstanceBuilders.ClrObjectInstanceBuilder.Initialize(IInstanceBuilderContext context, ViewNode viewNode, Boolean isNewInstance)
   at Microsoft.VisualStudio.DesignTools.Platform.InstanceBuilders.ViewNodeManager.InitializeInstance(IInstanceBuilder builder, ViewNode viewNode, Boolean isNewInstance)

The default contents of MainPage.Xaml for windows 8.1 project is :

<Page
    x:Class="HelloWorld.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:HelloWorld"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d">

    <Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">

    </Grid>
</Page>

The windows Phone 8.1 project loads the MainPage.xaml correctly. What is wrong with MainPage.xaml of Windows 8.1 project ?

Thanks,

Kunal

Answer 1

There is nothing wrong with the code.

>> using Visual Studio 2015 CTP5. 

You're using a beta version of Visual Studio. Try using VS2013 instead. There's probably a bug.

It could also be a problem with your Visual Studio install. Try repairing and/or reinstalling.

Does taking out the Background property fix the issue? (i.e. just leave a completely empty grid)

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I'm a self-taught noob amateur. Please take this into account when responding to my posts or when taking advice from me.

Answer 2

Yes.. removing Background property fixed the issue.. 

Will try repairing VS2015.

Thanks,

Kunal

Answer 3

I'm curious - did repairing it fix the issue?  I just noticed the exact same thing so I'm assuming it has to be a bug in CTP6.

Answer 4

I get the same error with a C# project. Most annoying.

Answer 5

If you're using VS 2015 CTP6 on Windows 10 build 10049 the XAML designer is completely broken. It's a known bug with that build. Even VS2013 doesn't work for me on that build. The only solution I found was to go back to build 10041.

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Visit http://blog.grogansoft.com/ for Windows development fun.