Avalonia/samples/BindingTest/MainWindow.paml

<Window xmlns="https://github.com/perspex">
  <StackPanel Orientation="Horizontal">
    <StackPanel Margin="18" Gap="4" Width="200">
      <TextBlock FontSize="16" Text="Simple Bindings"/>
      <TextBox Watermark="Two Way" UseFloatingWatermark="True" Text="{Binding StringValue}"/>
      <TextBox Watermark="One Way" UseFloatingWatermark="True" Text="{Binding StringValue, Mode=OneWay}"/>
      <TextBox Watermark="One Time" UseFloatingWatermark="True" Text="{Binding StringValue, Mode=OneTime}"/>
      <TextBox Watermark="One Way To Source" UseFloatingWatermark="True" Text="{Binding StringValue, Mode=OneWayToSource}"/>
    </StackPanel>
    <StackPanel Margin="18" Gap="4" Width="200">
      <TextBlock FontSize="16" Text="Collection Bindings"/>
      <TextBox Watermark="Items[1].StringValue" UseFloatingWatermark="True" Text="{Binding Items[1].StringValue}"/>
      <Button Command="{Binding ShuffleItems}">Shuffle</Button>
    </StackPanel>
    <StackPanel Margin="18" Gap="4" Width="200">
      <TextBlock FontSize="16" Text="Negated Bindings"/>
      <TextBox Watermark="Boolean String" UseFloatingWatermark="True" Text="{Binding BooleanString}"/>
      <CheckBox IsChecked="{Binding !BooleanString}">!BooleanString</CheckBox>
      <CheckBox IsChecked="{Binding !!BooleanString}">!!BooleanString</CheckBox>
    </StackPanel>
  </StackPanel>
</Window>