Avalonia/samples/BindingDemo/TestItemView.xaml

<UserControl xmlns="https://github.com/avaloniaui"
        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
        xmlns:viewModels="using:BindingDemo.ViewModels"
        x:Class="BindingDemo.TestItemView"
        x:DataType="viewModels:MainWindowViewModel+TestItem">
  <StackPanel>
    <TextBlock Classes="h1" Text="{Binding StringValue}"/>
    <TextBox Text="{Binding Detail}" AcceptsReturn="True"/>
  </StackPanel>
</UserControl>