Microsoft.Xaml.Behaviors.Wpf Issue

Issue with Microsoft.Xaml.Behaviors.Wpf package when loading XAML resources.

Annotated code

class App
{
    [STAThread]
    public static void Main(string[] args)
    {
        var app = new Application();
        // Loading XAML as a resource at run-time; we do this in our F# WPF application as well. Trying to port to .NET Core 3.0.
        var window = Application.LoadComponent(new Uri("/BehaviorIssueRepro.CSharp.Fail;component/Start.xaml", UriKind.Relative)) as Window;
        app.Run(window);
    }
}

This file is compiled as a resource in the project, so it can be loaded from the assembly at run-time.

<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:BehaviorIssueReproCSharpFail"
        xmlns:i="http://schemas.microsoft.com/xaml/behaviors"
        mc:Ignorable="d"
        Title="BehaviorIssueRepro.CSharp.Fail" 
        WindowStartupLocation="CenterScreen"
        Height="300" Width="400">
        
    <!-- Boom! -->
    <i:Interaction.Triggers>
        <!-- ...even without any triggers in the collection -->
    </i:Interaction.Triggers>
    
</Window>

Exception

XamlObjectWriterException: 'Cannot set unknown member '{http://schemas.microsoft.com/xaml/behaviors}Interaction.Triggers'.

System.Windows.Markup.XamlParseException
  HResult=0x80131501
  Message='Cannot set unknown member '{http://schemas.microsoft.com/xaml/behaviors}Interaction.Triggers'.' Line number '11' and line position '6'.
  Source=PresentationFramework
  StackTrace:
   at System.Windows.Markup.XamlReader.RewrapException(Exception e, IXamlLineInfo lineInfo, Uri baseUri)
   at System.Windows.Markup.WpfXamlLoader.Load(XamlReader xamlReader, IXamlObjectWriterFactory writerFactory, Boolean skipJournaledProperties, Object rootObject, XamlObjectWriterSettings settings, Uri baseUri)
   at System.Windows.Markup.WpfXamlLoader.Load(XamlReader xamlReader, Boolean skipJournaledProperties, Uri baseUri)
   at System.Windows.Markup.XamlReader.Load(XamlReader xamlReader, ParserContext parserContext)
   at System.Windows.Markup.XamlReader.Load(XmlReader reader, ParserContext parserContext, XamlParseMode parseMode, Boolean useRestrictiveXamlReader)
   at System.Windows.Markup.XamlReader.Load(Stream stream, ParserContext parserContext, Boolean useRestrictiveXamlReader)
   at System.Windows.Markup.XamlReader.Load(Stream stream, ParserContext parserContext)
   at System.Windows.Application.LoadComponent(Uri resourceLocator, Boolean bSkipJournaledProperties)
   at System.Windows.Application.LoadComponent(Uri resourceLocator)
   at BehaviorIssueRepro.CSharp.Fail.App.Main(String[] args) in C:\Users\foo\issue-microsoft-xaml-behaviors-wpf\src\BehaviorIssueRepro.CSharp.Fail\App.cs:line 12

Inner Exception 1:
XamlObjectWriterException: 'Cannot set unknown member '{http://schemas.microsoft.com/xaml/behaviors}Interaction.Triggers'.' Line number '11' and line position '6'.

Update

Converted to .NET 6 and newest nuget packages as of JAN 18 2022. Issues are stil there.

The C# project that mitigates the issue by using the BuildActioon=Page will instead produce an MSBuild null reference exeption when tried in an F# project - added new project to show that as well as a binlog file.

See also dotnet/wpf#3813