Avalonia/samples/ControlCatalog/ViewModelViewHost.xaml

<Style xmlns="https://github.com/avaloniaui" xmlns:cont="clr-namespace:ControlCatalog;assembly=ControlCatalog" 
       Selector="cont|ViewModelViewHost">
  <Setter Property="Template">
    <ControlTemplate>
      <ContentControl Name="PART_ContentPresenter"
                        Background="{TemplateBinding Background}"
                        BorderBrush="{TemplateBinding BorderBrush}"
                        BorderThickness="{TemplateBinding BorderThickness}"
                        Content="{TemplateBinding Content}"
                        Padding="{TemplateBinding Padding}"/>
    </ControlTemplate>
  </Setter>
</Style>