AoT: Failing to cast object to byte[]

[dotMorten]

Describe the bug

To Reproduce

1. Create a new WinUI 3 app, and enable it for AoT

2. Replace the MainWindow.xaml.cs code with the following:

       public MainWindow()
       {
           var settings = GetLocalSettings();
           if (!settings.Values.ContainsKey("Test"))
               settings.Values.Add("Test", new byte[] { 1, 2, 3, 4 });
           this.InitializeComponent();
       }
   
       private void myButton_Click(object sender, RoutedEventArgs e)
       {
           var settings = GetLocalSettings();
           var data = (byte[])settings.Values["Test"](); // BOOM! Unable to cast object of type 'WinRT.IInspectable' to type 'System.Byte[]'.
       }
   
       private ApplicationDataContainer GetLocalSettings()
       {
           var localSettings = ApplicationData.Current.LocalSettings;
           if (localSettings.Containers.TryGetValue("Settings", out var container))
               return container;
           return localSettings.CreateContainer("Settings", ApplicationDataCreateDisposition.Always);
       }

3. Run the app and click the button.
4. Observe the application crash: Unable to cast object of type 'WinRT.IInspectable' to type 'System.Byte[]'.

Expected behavior App settings gets the byte[].

Version Info WinAppSDK 1.6.0, CSWinRT 2.1.3

Additional context Also tried:

• .As<byte[]>()
• .As<IEnumerable<byte>>().ToArray()
• Enumerable.Cast<byte[]>((IEnumerable)settings.Values["Test"])

[dongle-the-gadget]

I was under the impression that arrays are illegal to use outside of parameters in the WinRT type system.

https://learn.microsoft.com/en-us/uwp/winrt-cref/winrt-type-system#array-parameters

[dotMorten]

@dongle-the-gadget are you saying we can't store any binary data (like data encrypted with the DataProtectionProvider) in the application settings? I mean it works fine - it's only in AoT mode it doesn't. .NET Native with UWP works fine also.

[dongle-the-gadget]

It works but seems like undocumented behavior. The supported list of types in docs also doesn’t mention arrays. I suppose though that you can probably cast the object into an IPropertyValue and get the array from there.

[dongle-the-gadget]

By any chance did you disable IReference support?

[dotMorten]

By any chance did you disable IReference support?

Not that I know off? The code is in a net8.0-windows library. No explicit reference to WindowsAppSDK.