Unable to instantiate a custom MediaPlayerElement

[vgromfeld]

Description

I'm using a custom control which inherits from MediaPlayerElement in my application. When creating an instance of my control, the application to throwing a NullReferenceException.

Steps To Reproduce

1. Create an UWP + .Net 9 application
2. Create a custom MediaPlayerElement control like:

public partial class CustomMediaPlayerElement : MediaPlayerElement
{
    public static readonly DependencyProperty IsPresenterEnabledProperty = DependencyProperty.Register(
        nameof(IsPresenterEnabled),
        typeof(bool),
        typeof(CustomMediaPlayerElement),
        new PropertyMetadata(true));

    public bool IsPresenterEnabled
    {
        get => (bool)GetValue(IsPresenterEnabledProperty);
        set => SetValue(IsPresenterEnabledProperty, value);
    }
}

3. Add this control to the main page

<StackPanel>
    <local:CustomMediaPlayerElement IsPresenterEnabled="True" />
</StackPanel>

4. Run the application

The application is throwing a NullReferenceException in:

Microsoft.Windows.UI.Xaml.dll!Windows.UI.Xaml.Controls.MediaPlayerElement.System.Runtime.InteropServices.ICustomQueryInterface.GetInterface(ref System.Guid iid, out nint ppv) Line 297	C#
System.Private.CoreLib.dll!System.Runtime.InteropServices.ComWrappers.CallICustomQueryInterface(object customQueryInterfaceMaybe, ref System.Guid iid, out nint ppObject)	Unknown
[Native to Managed Transition]	
[Managed to Native Transition]	
Microsoft.Windows.UI.Xaml.dll!Windows.UI.Xaml.Controls.MediaPlayerElement._IMediaPlayerElementFactoryMethods.CreateInstance(WinRT.IObjectReference _obj, object baseInterface, out nint innerInterface) Line 35	C#
Microsoft.Windows.UI.Xaml.dll!Windows.UI.Xaml.Controls.MediaPlayerElement.MediaPlayerElement() Line 218	C#
UWPAndDotNetNine.dll!UWPAndDotNetNine.CustomMediaPlayerElement.CustomMediaPlayerElement()	Unknown
UWPAndDotNetNine.dll!UWPAndDotNetNine.UWPAndDotNetNine_XamlTypeInfo.XamlTypeInfoProvider.Activate_0_CustomMediaPlayerElement() Line 253	C#
UWPAndDotNetNine.dll!UWPAndDotNetNine.UWPAndDotNetNine_XamlTypeInfo.XamlUserType.ActivateInstance() Line 462	C#
Microsoft.Windows.UI.Xaml.dll!ABI.Windows.UI.Xaml.Markup.IXamlType.Do_Abi_ActivateInstance_12(nint thisPtr, nint* result) Line 155	C#
[Native to Managed Transition]	
[Managed to Native Transition]	
Microsoft.Windows.UI.Xaml.dll!ABI.Windows.UI.Xaml.IApplicationStaticsMethods.LoadComponent(WinRT.IObjectReference _obj, object component, System.Uri resourceLocator, Windows.UI.Xaml.Controls.Primitives.ComponentResourceLocation componentResourceLocation) Line 71	C#
Microsoft.Windows.UI.Xaml.dll!Windows.UI.Xaml.Application.LoadComponent(object component, System.Uri resourceLocator, Windows.UI.Xaml.Controls.Primitives.ComponentResourceLocation componentResourceLocation) Line 320	C#
UWPAndDotNetNine.dll!UWPAndDotNetNine.MainPage.InitializeComponent() Line 37	C#
UWPAndDotNetNine.dll!UWPAndDotNetNine.MainPage.MainPage() Line 25	C#
UWPAndDotNetNine.dll!UWPAndDotNetNine.UWPAndDotNetNine_XamlTypeInfo.XamlTypeInfoProvider.Activate_3_MainPage() Line 254	C#
UWPAndDotNetNine.dll!UWPAndDotNetNine.UWPAndDotNetNine_XamlTypeInfo.XamlUserType.ActivateInstance() Line 462	C#
Microsoft.Windows.UI.Xaml.dll!ABI.Windows.UI.Xaml.Markup.IXamlType.Do_Abi_ActivateInstance_12(nint thisPtr, nint* result) Line 155	C#
[Native to Managed Transition]	
[Managed to Native Transition]	
Microsoft.Windows.UI.Xaml.dll!ABI.Windows.UI.Xaml.Controls.IFrameMethods.Navigate(WinRT.IObjectReference _obj, System.Type sourcePageType, object parameter) Line 70	C#
Microsoft.Windows.UI.Xaml.dll!Windows.UI.Xaml.Controls.Frame.Navigate(System.Type sourcePageType, object parameter) Line 389	C#
UWPAndDotNetNine.dll!UWPAndDotNetNine.App.OnLaunched(Windows.ApplicationModel.Activation.LaunchActivatedEventArgs e) Line 52	C#
Microsoft.Windows.UI.Xaml.dll!Windows.UI.Xaml.Application.Windows.UI.Xaml.IApplicationOverrides.OnLaunched(Windows.ApplicationModel.Activation.LaunchActivatedEventArgs args) Line 404	C#
Microsoft.Windows.UI.Xaml.dll!ABI.Windows.UI.Xaml.IApplicationOverrides.Do_Abi_OnLaunched_1(nint thisPtr, nint args) Line 51	C#

Expected Behavior

The application should run.

Version Info

TargetFramework = net9.0-windows10.0.26100.0
Microsoft.Windows.CsWinRT = 2.2.0

Additional Context

Sample application: CustomMediaPlayerElement.zip