Avalonia/samples/IntegrationTestApp/Pages/ListBoxPage.axaml

<UserControl xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             xmlns:pages="using:IntegrationTestApp.Pages"
             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
             x:Class="IntegrationTestApp.Pages.ListBoxPage"
             x:DataType="pages:ListBoxPage">
  <DockPanel>
    <StackPanel DockPanel.Dock="Bottom">
      <Button Name="ListBoxSelectionClear" Click="ListBoxSelectionClear_Click">Clear Selection</Button>
    </StackPanel>
    <ListBox Name="BasicListBox" ItemsSource="{Binding ListBoxItems}" SelectionMode="Multiple"/>
  </DockPanel>
</UserControl>