Avalonia/src/Avalonia.Themes.Fluent/Controls/MenuItem.xaml

<Styles xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:conv="clr-namespace:Avalonia.Controls.Converters;assembly=Avalonia.Controls"
        xmlns:sys="clr-namespace:System;assembly=netstandard">
  <Design.PreviewWith>
    <Border Padding="20"
            Width="400"
            Height="200">
      <Menu VerticalAlignment="Top">
        <MenuItem Header="File">
          <MenuItem Header="Disabled"
                    IsEnabled="False" />
          <MenuItem Header="New"
                    InputGesture="Ctrl+N">
            <MenuItem Header="XML" />
          </MenuItem>
          <MenuItem Header="Open">
            <MenuItem.Icon>
              <CheckBox BorderThickness="0"
                        IsHitTestVisible="False"
                        IsChecked="True" />
            </MenuItem.Icon>
          </MenuItem>
          <Separator />
          <MenuItem Header="Exit"
                    InputGesture="Alt+F4" />
        </MenuItem>
        <MenuItem Header="Edit">
          <MenuItem Header="Go To">
            <MenuItem Header="Go To Line" />
          </MenuItem>
        </MenuItem>
        <MenuItem Header="View">
          <MenuItem Header="Designer"
                    InputGesture="Shift+F7" />
        </MenuItem>
        <MenuItem Header="Project">
          <MenuItem Header="Add class" />
        </MenuItem>
      </Menu>
    </Border>
  </Design.PreviewWith>

  <Styles.Resources>
    <conv:PlatformKeyGestureConverter x:Key="KeyGestureConverter" />
    <x:Double x:Key="MenuFlyoutSubItemPopupHorizontalOffset">-4</x:Double>
    <Thickness x:Key="MenuFlyoutScrollerMargin">0,4,0,4</Thickness>
    <Thickness x:Key="MenuIconPresenterMargin">0,0,12,0</Thickness>
    <Thickness x:Key="MenuInputGestureTextMargin">24,0,0,0</Thickness>
    <StreamGeometry x:Key="MenuItemChevronPathData">M 1,0 10,10 l -9,10 -1,-1 L 8,10 -0,1 Z</StreamGeometry>
  </Styles.Resources>

  <Style Selector="MenuItem">
    <Setter Property="Background" Value="{DynamicResource MenuFlyoutItemBackground}" />
    <Setter Property="Foreground" Value="{DynamicResource MenuFlyoutItemForeground}" />
    <Setter Property="Padding" Value="{DynamicResource MenuFlyoutItemThemePadding}" />
    <Setter Property="FontSize" Value="{DynamicResource ControlContentThemeFontSize}" />
    <Setter Property="Template">
      <ControlTemplate>
        <Panel>
          <Border Name="PART_LayoutRoot"
                  Padding="{TemplateBinding Padding}"
                  Background="{TemplateBinding Background}"
                  BorderBrush="{TemplateBinding BorderBrush}"
                  BorderThickness="{TemplateBinding BorderThickness}">
            <Grid>
              <Grid.ColumnDefinitions>
                <ColumnDefinition Width="Auto"
                                  SharedSizeGroup="MenuItemIcon" />
                <ColumnDefinition Width="*" />
                <ColumnDefinition Width="Auto"
                                  SharedSizeGroup="MenuItemIGT" />
                <ColumnDefinition Width="Auto"
                                  SharedSizeGroup="MenuItemChevron" />
              </Grid.ColumnDefinitions>
              <ContentPresenter Name="PART_IconPresenter"
                                Content="{TemplateBinding Icon}"
                                Width="16"
                                Height="16"
                                Margin="{DynamicResource MenuIconPresenterMargin}"
                                HorizontalAlignment="Center"
                                VerticalAlignment="Center" />

              <ContentPresenter Name="PART_HeaderPresenter"
                                Content="{TemplateBinding Header}"
                                VerticalAlignment="Center"
                                HorizontalAlignment="Stretch"
                                Grid.Column="1">
                <ContentPresenter.DataTemplates>
                  <DataTemplate DataType="sys:String">
                    <AccessText Text="{Binding}" />
                  </DataTemplate>
                </ContentPresenter.DataTemplates>
              </ContentPresenter>
              <TextBlock x:Name="PART_InputGestureText"
                         Grid.Column="2"
                         Classes="CaptionTextBlockStyle"
                         Margin="{DynamicResource MenuInputGestureTextMargin}"
                         Text="{TemplateBinding InputGesture, Converter={StaticResource KeyGestureConverter}}"
                         HorizontalAlignment="Right"
                         VerticalAlignment="Center" />
              <Path Name="PART_ChevronPath"
                    Stretch="Uniform"
                    Width="8"
                    Height="16"
                    Data="{StaticResource MenuItemChevronPathData}"
                    Margin="{DynamicResource MenuFlyoutItemChevronMargin}"
                    VerticalAlignment="Center"
                    Grid.Column="3" />
            </Grid>
          </Border>
          <Popup Name="PART_Popup"
                 WindowManagerAddShadowHint="False"
                 PlacementMode="Right"
                 OverlayInputPassThroughElement="{Binding $parent[MenuItem]}"
                 HorizontalOffset="{DynamicResource MenuFlyoutSubItemPopupHorizontalOffset}"
                 IsLightDismissEnabled="True"
                 IsOpen="{TemplateBinding IsSubMenuOpen, Mode=TwoWay}">
            <Border Background="{DynamicResource MenuFlyoutPresenterBackground}"
                    BorderBrush="{DynamicResource MenuFlyoutPresenterBorderBrush}"
                    BorderThickness="{DynamicResource MenuFlyoutPresenterBorderThemeThickness}"
                    Padding="{DynamicResource MenuFlyoutPresenterThemePadding}"
                    MaxWidth="{DynamicResource FlyoutThemeMaxWidth}"
                    MinHeight="{DynamicResource MenuFlyoutThemeMinHeight}"
                    HorizontalAlignment="Stretch"
                    CornerRadius="{DynamicResource OverlayCornerRadius}">
              <ScrollViewer Classes="menuscroller">
                <ItemsPresenter Name="PART_ItemsPresenter"
                                Items="{TemplateBinding Items}"
                                ItemsPanel="{TemplateBinding ItemsPanel}"
                                ItemTemplate="{TemplateBinding ItemTemplate}"
                                Margin="{DynamicResource MenuFlyoutScrollerMargin}"
                                Grid.IsSharedSizeScope="True" />
              </ScrollViewer>
            </Border>
          </Popup>
        </Panel>
      </ControlTemplate>
    </Setter>
  </Style>

  <Style Selector="Menu > MenuItem">
    <Setter Property="Template">
      <ControlTemplate>
        <Border Name="PART_LayoutRoot"
                Background="{TemplateBinding Background}"
                BorderBrush="{TemplateBinding BorderBrush}"
                BorderThickness="{TemplateBinding BorderThickness}">
          <Panel>
            <ContentPresenter Name="PART_HeaderPresenter"
                              Content="{TemplateBinding Header}"
                              VerticalAlignment="Center"
                              HorizontalAlignment="Stretch"
                              Margin="{TemplateBinding Padding}">
              <ContentPresenter.DataTemplates>
                <DataTemplate DataType="sys:String">
                  <AccessText Text="{Binding}" />
                </DataTemplate>
              </ContentPresenter.DataTemplates>
            </ContentPresenter>
            <Popup Name="PART_Popup"
                   WindowManagerAddShadowHint="False"
                   MinWidth="{Binding Bounds.Width, RelativeSource={RelativeSource TemplatedParent}}"
                   IsLightDismissEnabled="True"
                   IsOpen="{TemplateBinding IsSubMenuOpen, Mode=TwoWay}"
                   OverlayInputPassThroughElement="{Binding $parent[Menu]}">
              <Border Background="{DynamicResource MenuFlyoutPresenterBackground}"
                      BorderBrush="{DynamicResource MenuFlyoutPresenterBorderBrush}"
                      BorderThickness="{DynamicResource MenuFlyoutPresenterBorderThemeThickness}"
                      Padding="{DynamicResource MenuFlyoutPresenterThemePadding}"
                      MaxWidth="{DynamicResource FlyoutThemeMaxWidth}"
                      MinHeight="{DynamicResource MenuFlyoutThemeMinHeight}"
                      HorizontalAlignment="Stretch"
                      CornerRadius="{DynamicResource OverlayCornerRadius}">
                <ScrollViewer Classes="menuscroller">
                  <ItemsPresenter Name="PART_ItemsPresenter"
                                  Items="{TemplateBinding Items}"
                                  ItemsPanel="{TemplateBinding ItemsPanel}"
                                  ItemTemplate="{TemplateBinding ItemTemplate}"
                                  Margin="{DynamicResource MenuFlyoutScrollerMargin}"
                                  Grid.IsSharedSizeScope="True" />
                </ScrollViewer>
              </Border>
            </Popup>
          </Panel>
        </Border>
      </ControlTemplate>
    </Setter>
  </Style>

  <Style Selector="MenuItem">
    <!--  Narrow padding should be used for mouse input, when non-narrow one should be used for touch input in future.  -->
    <Setter Property="Padding" Value="{DynamicResource MenuFlyoutItemThemePaddingNarrow}" />
  </Style>

  <Style Selector="Menu > MenuItem">
    <!--  Custom padding for Menu > MenuItem  -->
    <Setter Property="Padding" Value="{DynamicResource MenuBarItemPadding}" />
  </Style>

  <Style Selector="MenuItem /template/ ContentPresenter#PART_IconPresenter">
    <Setter Property="IsVisible" Value="False" />
  </Style>
  <Style Selector="MenuItem:icon /template/ ContentPresenter#PART_IconPresenter">
    <Setter Property="IsVisible" Value="True" />
  </Style>

  <Style Selector="MenuItem /template/ TextBlock#PART_InputGestureText">
    <Setter Property="Foreground" Value="{DynamicResource MenuFlyoutItemKeyboardAcceleratorTextForeground}" />
  </Style>
  <Style Selector="MenuItem /template/ Path#PART_ChevronPath">
    <Setter Property="Fill" Value="{DynamicResource MenuFlyoutSubItemChevron}" />
  </Style>

  <Style Selector="MenuItem:selected /template/ Border#PART_LayoutRoot">
    <Setter Property="Background" Value="{DynamicResource MenuFlyoutItemBackgroundPointerOver}" />
  </Style>
  <Style Selector="MenuItem:selected /template/ ContentPresenter#PART_HeaderPresenter">
    <Setter Property="TextBlock.Foreground" Value="{DynamicResource MenuFlyoutItemForegroundPointerOver}" />
  </Style>
  <Style Selector="MenuItem:selected /template/ TextBlock#PART_InputGestureText">
    <Setter Property="Foreground" Value="{DynamicResource MenuFlyoutItemKeyboardAcceleratorTextForegroundPointerOver}" />
  </Style>
  <Style Selector="MenuItem:selected /template/ Path#PART_ChevronPath">
    <Setter Property="Fill" Value="{DynamicResource MenuFlyoutSubItemChevronPointerOver}" />
  </Style>

  <!--  Listen for PART_LayoutRoot:pointerover, so it will not be triggered when subitem is pressed  -->
  <Style Selector="MenuItem:pressed /template/ Border#PART_LayoutRoot:pointerover">
    <Setter Property="Background" Value="{DynamicResource MenuFlyoutItemBackgroundPressed}" />
  </Style>
  <Style Selector="MenuItem:pressed /template/ Border#PART_LayoutRoot:pointerover ContentPresenter#PART_HeaderPresenter">
    <Setter Property="TextBlock.Foreground" Value="{DynamicResource MenuFlyoutItemForegroundPressed}" />
  </Style>
  <Style Selector="MenuItem:pressed /template/ Border#PART_LayoutRoot:pointerover TextBlock#PART_InputGestureText">
    <Setter Property="Foreground" Value="{DynamicResource MenuFlyoutItemKeyboardAcceleratorTextForegroundPressed}" />
  </Style>
  <Style Selector="MenuItem:pressed /template/ Border#PART_LayoutRoot:pointerover Path#PART_ChevronPath">
    <Setter Property="Fill" Value="{DynamicResource MenuFlyoutSubItemChevronPressed}" />
  </Style>

  <Style Selector="MenuItem:disabled /template/ Border#PART_LayoutRoot">
    <Setter Property="Background" Value="{DynamicResource MenuFlyoutItemBackgroundDisabled}" />
  </Style>
  <Style Selector="MenuItem:disabled /template/ ContentPresenter#PART_HeaderPresenter">
    <Setter Property="TextBlock.Foreground" Value="{DynamicResource MenuFlyoutItemForegroundDisabled}" />
  </Style>
  <Style Selector="MenuItem:disabled /template/ TextBlock#PART_InputGestureText">
    <Setter Property="Foreground" Value="{DynamicResource MenuFlyoutItemKeyboardAcceleratorTextForegroundDisabled}" />
  </Style>
  <Style Selector="MenuItem:disabled /template/ Path#PART_ChevronPath">
    <Setter Property="Fill" Value="{DynamicResource MenuFlyoutSubItemChevronDisabled}" />
  </Style>

  <Style Selector="MenuItem:open /template/ Path#PART_ChevronPath">
    <Setter Property="Fill" Value="{DynamicResource MenuFlyoutSubItemChevronSubMenuOpened}" />
  </Style>

  <Style Selector="MenuItem:empty /template/ Path#PART_ChevronPath">
    <Setter Property="IsVisible" Value="False" />
  </Style>

  <Style Selector="MenuItem:separator">
    <Setter Property="Template">
      <ControlTemplate>
        <Separator />
      </ControlTemplate>
    </Setter>
  </Style>

  <Style Selector="MenuItem > Separator, ContextMenu > Separator">
    <Setter Property="Background" Value="{DynamicResource SystemControlForegroundBaseMediumLowBrush}" />
    <Setter Property="HorizontalAlignment" Value="Stretch" />
    <Setter Property="Margin" Value="{DynamicResource MenuFlyoutSeparatorThemePadding}" />
    <Setter Property="Height" Value="{DynamicResource MenuFlyoutSeparatorThemeHeight}" />
  </Style>
</Styles>