Avalonia/samples/ControlCatalog/Pages/TabbedPage/TabbedPageCollectionPage.xaml

<UserControl xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             x:Class="ControlCatalog.Pages.TabbedPageCollectionPage">
  <DockPanel>
    <ScrollViewer DockPanel.Dock="Right" Width="260">
      <StackPanel Margin="12" Spacing="8">
        <TextBlock Text="Page Collection" FontWeight="SemiBold" FontSize="16"
                   Foreground="{DynamicResource SystemControlHighlightAccentBrush}" />

        <TextBlock FontSize="12" Opacity="0.7" TextWrapping="Wrap"
                   Text="Populate a TabbedPage by adding ContentPage objects directly to the Pages collection. Add and remove pages dynamically at runtime." />

        <Separator />

        <TextBlock Text="Tab Management" FontWeight="SemiBold" FontSize="13" />
        <Button Content="Add Page" Click="OnAddPage" HorizontalAlignment="Stretch" />
        <Button Content="Remove Last Page" Click="OnRemoveLast" HorizontalAlignment="Stretch" />
        <Button Content="Clear All" Click="OnClearAll" HorizontalAlignment="Stretch" />

        <Separator />

        <TextBlock x:Name="StatusText" Text="3 tabs" Opacity="0.7" TextWrapping="Wrap" />
      </StackPanel>
    </ScrollViewer>

    <Border DockPanel.Dock="Right" Width="1" Background="{DynamicResource SystemControlForegroundBaseMediumLowBrush}" />

    <Border Margin="12"
            BorderBrush="{DynamicResource SystemControlForegroundBaseMediumLowBrush}"
            BorderThickness="1"
            CornerRadius="6"
            ClipToBounds="True">
      <TabbedPage x:Name="DemoTabs" TabPlacement="Top">
        <ContentPage Header="Today">
          <StackPanel Margin="16" Spacing="8">
            <TextBlock Text="Today" FontSize="24" FontWeight="Bold" />
            <TextBlock Text="Your daily overview and tasks." TextWrapping="Wrap" Opacity="0.7" />
          </StackPanel>
        </ContentPage>
        <ContentPage Header="Schedule">
          <StackPanel Margin="16" Spacing="8">
            <TextBlock Text="Schedule" FontSize="24" FontWeight="Bold" />
            <TextBlock Text="Upcoming events and appointments." TextWrapping="Wrap" Opacity="0.7" />
          </StackPanel>
        </ContentPage>
        <ContentPage Header="Settings">
          <StackPanel Margin="16" Spacing="8">
            <TextBlock Text="Settings" FontSize="24" FontWeight="Bold" />
            <TextBlock Text="Manage your preferences." TextWrapping="Wrap" Opacity="0.7" />
          </StackPanel>
        </ContentPage>
      </TabbedPage>
    </Border>
  </DockPanel>
</UserControl>