XamlTypeInfo forgets to generate type information if only used as type

[huoyaoyuan]

Describe the bug

XamlTypeInfo forgets to generate type information if the type is only used as type xaml, not object or property.

Steps to reproduce the bug

1. Create a project with WinUI3, and install CommunityToolkit.WinUI.UI 7.1.1-preview3
2. Create an enum named MyEnum
3. Add following xaml:

    xmlns:wctk="using:CommunityToolkit.WinUI.UI"

<ListView ItemsSource="{wctk:EnumValues Type=local:MyEnum}" />

4. The markup extension receives a null type, and fails to provide values of the enum.

Expected behavior

Enum values shown in the ListView.

Screenshots

N/A

NuGet package version

WinUI 3 - Windows App SDK 1.0.0-preview3

Windows app type

• UWP
• Win32

Device form factor

Desktop

Windows version

May 2021 Update (19043)

Additional context

The workaround is to create a dummy object:

        <StackPanel.Resources>
            <local:MyEnum x:Key="__Dummy">0</local:MyEnum>
        </StackPanel.Resources>

Having a control with the enum as a property will make it generates correctly.

[StephenLPeters]

@RealTommyKlein and @evelynwu-msft FYI

[RealTommyKlein]

Thanks for the report - this will be fixed in Windows App SDK 1.1. As an alternative workaround, you can also add the Microsoft.UI.Xaml.Data.Bindable attribute to the types being assigned to the property, e.g.:

[Microsoft.UI.Xaml.Data.Bindable]
enum MyEnum
{
    ....
}

[RealTommyKlein]

This is fixed for the upcoming Windows App SDK 1.1 release - also, closing this issue as a dupe of #4161