Avalonia/samples/ControlCatalog/Pages/ContextMenuPage.xaml

<UserControl xmlns="https://github.com/avaloniaui">
    <StackPanel Orientation="Vertical" Gap="4">
        <TextBlock Classes="h1">Context Menu</TextBlock>
        <TextBlock Classes="h2">A right click menu that can be applied to any control.</TextBlock>

        <StackPanel Orientation="Horizontal"
              Margin="0,16,0,0"
              HorizontalAlignment="Center"
              Gap="16">
            <Border Background="{DynamicResource ThemeAccentBrush}"
              Padding="48,48,48,48">
                <Border.ContextMenu>
                    <ContextMenu>
                        <MenuItem Header="Standard _Menu Item"/>
                        <Separator/>
                        <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>
                    </ContextMenu>
                </Border.ContextMenu>
                <TextBlock Text="Right Click Here"/>
            </Border>
        </StackPanel>
    </StackPanel>
</UserControl>