GetDependencyObjectForXBind() not found in a usercontrol

[stefanolson]

Still in the process of upgrading from Uno 3.4 to 4.4. I now have a new problem that I cannot figure out. I've got a control derived from UserControl and in the autogenerated output .g.cs file, it's telling me that the HorizontalAlignment property doesn't exist on that control:

new global::XXXX.Controls.BorderControl
{
	
	// WARNING Property HorizontalAlignment does not exist on {using:XXX.Controls}BorderControl, name is HorizontalAlignment, preferrednamespace using:XXX.Controls
	// Source ..\..\..\..\..\..\Views\FillInFormView.xaml (Line 330:18)
}
.FillInFormView_003843894a43acaf4392ffc8726f9615_XamlApply((FillInFormView_003843894a43acaf4392ffc8726f9615XamlApplyExtensions.XamlApplyHandler10)(c37 => 
{
	global::Windows.UI.Xaml.Controls.Grid.SetRow(c37, 1/* int/, 1, Grid/Row */);
	global::Windows.UI.Xaml.Controls.Grid.SetRowSpan(c37, 2/* int/, 2, Grid/RowSpan */);
	global::Windows.UI.Xaml.Controls.Grid.SetColumn(c37, 0/* int/, 0, Grid/Column */);
	c37.GetDependencyObjectForXBind().SetBinding(
		"Visibility",
		new Windows.UI.Xaml.Data.Binding()
		{
			Path = @"ShowTemplatesBar"/* Windows.UI.Xaml.PropertyPath/Windows.UI.Xaml.PropertyPath, ShowTemplatesBar, /_PositionalParameters */,
			Converter = (global::Windows.UI.Xaml.Data.IValueConverter)global::Uno.UI.ResourceResolverSingleton.Instance.ResolveResourceStatic("BooleanToVisibilityConverter", typeof(global::Windows.UI.Xaml.Data.IValueConverter), context: global::LegacyDocsControls.GlobalStaticResources.__ParseContext_),
		}
	);
}
))

and nor can it set the binding, with this error:
Error CS1061: 'DependencyObject' does not contain a definition for 'SetBinding' and no accessible extension method 'SetBinding' accepting a first argument of type 'DependencyObject' could be found (are you missing a using directive or an assembly reference?)

xaml code for above:
<controls1:BorderControl HorizontalAlignment="Right" Grid.Row="1" Grid.RowSpan="2" Grid.Column="0" Visibility="{Binding ShowTemplatesBar, Converter={StaticResource BooleanToVisibilityConverter}}"/>

So I've copied the control to another project and it doesn't have this problem. The difference is that both controls are in a class library.

So I must be missing something. What am I missing?

[stefanolson]

I've just rebuilt my library in WinUi. In the hope that would fix the problem but I'm having what appears to be the same issue: Error CS1061: 'DependencyObject' does not contain a definition for 'SetBinding' and no accessible extension method 'SetBinding' accepting a first argument of type 'DependencyObject' could be found (are you missing a using directive or an assembly reference?)

[stefanolson]

I seem to have solved it by adding in the parent class into the .cs file. e.g:
partial class BorderControl:UserControl
This concerns me because it makes me think it isn't actually compiling the page but will wait and see once I've got the rest of everything operational.