ItemsPanelTemplate doesn't support AoT-safe binding

[Arlodotexe]

We are encountering issues when trying to bind properties within an ItemsPanelTemplate. Currently, we have this code in our project:

        <GridView Name="GridView"
                  ItemTemplate="{StaticResource StaggeredTemplate}"
                  ItemsSource="{x:Bind ColorsCollection, Mode=OneWay}">

            <GridView.ItemsPanel>
                <ItemsPanelTemplate>
                    <controls:StaggeredPanel ColumnSpacing="{Binding ColumnSpacing, ElementName=ThisSamplePage, Mode=OneWay}"
                                             DesiredColumnWidth="{Binding DesiredColumnWidth, ElementName=ThisSamplePage, Mode=OneWay}"
                                             RowSpacing="{Binding RowSpacing, ElementName=ThisSamplePage, Mode=OneWay}" />
                </ItemsPanelTemplate>
            </GridView.ItemsPanel>
        </GridView>

This will crash at runtime when compiled under NativeAoT for both the WindowsAppSDK and UWP with modern .NET.

Removing the binding on the ItemsPanelTemplate fixes the issue, as shown in the image below:

Unfortunately, we cannot use x:Bind here because it results in the following error:

1>StaggeredPanelSample.xaml(42,22): XamlCompiler error WMC1111: DataTemplates containing x:Bind need a DataType to be specified using 'x:DataType'
1>Done building project \"Primitives.Samples.csproj\" -- FAILED.

Neither a DataTemplate nor its accompanying x:DataType can be added here since ItemsPanelTemplate is already a template and must have a first child of type Panel.

Looking through documentation for 'official' examples of binding properties on an ItemsPanelTemplate, I'm not finding any where these properties are bound, whether using {Binding}, {x:Bind}, or {TemplateBinding}.

Using {Binding} worked before, but it's not AoT safe and x:Bind doesn't seem to be compatible. What is the platform recommended approach here?

[hawkerm]

Trying to configure the size of a (toolkit) UniformGrid based on the number of items in the parent ItemsControl, but then can't use x:Bind due to ItemsPanelTemplate not being allowed to use x:DataType

XamlCompiler error WMC1111: DataTemplates containing x:Bind need a DataType to be specified using 'x:DataType'

If I try and add the DataType you get instead:

XamlCompiler error WMC0908: DataType is only allowed for DataTemplate.

I can't give the control in the template a name, so I need to use regular binding and reach up with ancestor helpers, use Binding with ElementName, or use the Loaded event, etc...