TokenizedTextBox throws "NamedResource Not Found. (0x80073B17)" upon load with AppSDK preview 3

[gus33000]

Describe the bug

Upon loading a TokenizedTextBox control in an App SDK packaged or unpackaged project, when using localized properties, the following exception is thrown:

• Is this bug a regression in the toolkit? If so, what toolkit version did you last see it work: 7.1.1 (UWP)

Steps to Reproduce

• Can this be reproduced in the Sample App? (Either in a sample as-is or with new XAML pasted in the editor.) If so, please provide custom XAML or steps to reproduce. If not, let us know why it can't be reproduced (e.g. more complex setup, environment, dependencies, etc...)

No sample app is available for App SDK preview 3 as far as I'm aware so I cannot test it here.

Steps to reproduce the behavior:

1. Create a new AppSDK preview 3 packaged project with WinUI 3
2. Add a reference to the CommunityToolkit 7.1.1-preview3
3. Add the following xaml in mainwindow.xaml:

<Window
    x:Class="App1.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:App1"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:ctk="using:CommunityToolkit.WinUI.UI.Controls"
    mc:Ignorable="d">

    <ctk:TokenizingTextBox Margin="0,4"
                           CornerRadius="8"
                           ItemsSource="{x:Bind TestCollection, Mode=TwoWay}"
                           PlaceholderText="{local:ResourceString Name=TestPlaceholder}"
                           TokenDelimiter=";" />
</Window>

4. Add the following code in mainwindow.xaml.cs

using Microsoft.UI.Xaml;
using Microsoft.UI.Xaml.Controls;
using Microsoft.UI.Xaml.Controls.Primitives;
using Microsoft.UI.Xaml.Data;
using Microsoft.UI.Xaml.Input;
using Microsoft.UI.Xaml.Markup;
using Microsoft.UI.Xaml.Media;
using Microsoft.UI.Xaml.Navigation;
using Microsoft.Windows.ApplicationModel.Resources;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.Foundation;
using Windows.Foundation.Collections;

// To learn more about WinUI, the WinUI project structure,
// and more about our project templates, see: http://aka.ms/winui-project-info.

namespace App1
{
    public static class ResourceStringHelper
    {
        /// <summary>
        /// Gets the following resource string from the application resx files
        /// This method cannot be called from any thread.
        /// </summary>
        /// <param name="id">The identifier of the resource string</param>
        /// <returns></returns>
        public static string GetStringFromResources(string id)
        {
            ResourceLoader resourceLoader = new ResourceLoader();
            return resourceLoader.GetString(id);
        }
    }

    [MarkupExtensionReturnType(ReturnType = typeof(string))]
    public sealed class ResourceString : MarkupExtension
    {
        public string Name
        {
            get; set;
        }

        protected override object ProvideValue()
        {
            return ResourceStringHelper.GetStringFromResources(Name);
        }
    }

    /// <summary>
    /// An empty window that can be used on its own or navigated to within a Frame.
    /// </summary>
    public sealed partial class MainWindow : Window
    {
        public ObservableCollection<string> TestCollection = new();

        public MainWindow()
        {
            this.InitializeComponent();
        }
    }
}

5. Add a new Resources.resw, in Strings\en\Resources.resw, with a single key/value pair: "TestPlaceholder" => "I'm a test"
6. In configuration manager, tick the deploy checkbox so visual studio deploys the application
7. Run the application
8. An exception is thrown

Expected behavior

The control should load and work properly without an exception being thrown.

Environment

NuGet Package(s):

• CommunityToolkit.WinUI.UI.Controls
• Microsoft.WindowsAppSDK (1.0.0-preview3)
• Microsoft.Windows.SDK.BuildTools (10.0.20348.19)

Package Version(s):

7.1.1-preview3

Windows 10 Build Number:

• Fall Creators Update (16299)
• April 2018 Update (17134)
• October 2018 Update (17763)
• May 2019 Update (18362)
• May 2020 Update (19041)
• Insider Build (22000.282)

App min and target version:

• Fall Creators Update (16299)
• April 2018 Update (17134)
• October 2018 Update (17763)
• May 2019 Update (18362)
• May 2020 Update (19041)

Device form factor:

• Desktop
• Xbox
• Surface Hub
• IoT

Visual Studio version:

• 2022 (17.Preview/17.0.0-pre.7.0+31825.309)

Additional context

The control works fine without the localized string, removing it makes it work. However the issue is not the local:ResourceString markup extension as using it in a textblock works fine, as such:

<Window
    x:Class="App1.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:App1"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:ctk="using:CommunityToolkit.WinUI.UI.Controls"
    mc:Ignorable="d">

    <TextBlock Text="{local:ResourceString Name=TestPlaceholder}"/>
</Window>

Hello gus33000, thank you for opening an issue with us!

I have automatically added a "needs triage" label to help get things started. Our team will analyze and investigate the issue, and escalate it to the relevant team if possible. Other community members may also look into the issue and provide feedback 🙌

[Nirmal4G]

We recently fixed a similar resource loading issue filed in #4279 via PR #4310. At the surface, it doesn't seem to be related to that.

I see that you're loading resources from a class instead of x:Uid attribute. Does it only fails with the Toolkit package? What about other versions?

[gus33000]

Hello,

It does work correctly for all other controls in my project that are not from the toolkit, and worked fine with the toolkit in UWP projects. I can see if the issue happens with other controls from the toolkit in WinUI 3 but I got no issues on 7.1.1 (UWP).