Avalonia/samples/ControlCatalog/Pages/MenuPage.xaml

<UserControl xmlns="https://github.com/perspex">
  <StackPanel Orientation="Vertical" Gap="4">
    <TextBlock Classes="h1">Menu</TextBlock>
    <TextBlock Classes="h2">A window menu</TextBlock>

    <StackPanel Orientation="Horizontal"
              Margin="0,16,0,0"
              HorizontalAlignment="Center"
              Gap="16">
      <Menu>
        <MenuItem Header="_First">
          <MenuItem Header="Standard _Menu Item"/>
          <MenuItem Header="Menu with _Submenu">
            <MenuItem Header="Submenu _1"/>
            <MenuItem Header="Submenu _2"/>
          </MenuItem>
          <MenuItem Header="Menu Item with _Icon">
            <MenuItem.Icon>
              <Image Source="resm:ControlCatalog.Assets.github_icon.png"/>
            </MenuItem.Icon>
          </MenuItem>
          <MenuItem Header="Menu Item with _Checkbox">
            <MenuItem.Icon>
              <CheckBox BorderThickness="0" IsHitTestVisible="False" IsChecked="True"/>
            </MenuItem.Icon>
          </MenuItem>
        </MenuItem>
        <MenuItem Header="_Second">
          <MenuItem Header="Second _Menu Item"/>
        </MenuItem>
      </Menu>
    </StackPanel>
  </StackPanel>
</UserControl>