子菜单弹出背景透明

Question

如何使子菜单弹出框/边框透明？

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我设置了菜单和子菜单的样式。当您选择具有子菜单的菜单项时，您会在样式选择周围看到一个灰色框。我该如何设计？

查看菜单Menu Styles and Templates 的样式时，我尝试了控件Border、ScrollViewer 和Stackpanel 的多种样式覆盖。我试图覆盖颜色。

<Menu.Resources>
    <Style TargetType="Popup"><Setter Property="AllowsTransparency" Value="True" /></Style>

    <Style TargetType="ScrollViewer"><Setter Property="Background"  Value="Green" /></Style>
    <Style TargetType="StackPanel"><Setter Property="Background"    Value="Firebrick"/></Style>
    <Style TargetType="Border"><Setter Property="Background"        Value="Firebrick" /></Style>   

    <SolidColorBrush x:Key="MenuPopuBrush"      Color="Firebrick" />
    <SolidColorBrush x:Key=" BorderMediumColor" Color="Firebrick" />          
</Menu.Resources>

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小例子

<Menu Foreground="Transparent">
   <MenuItem Header="Item 1">
        <MenuItem Header="Sub 1a" />
        <MenuItem Header="Sub 1b"/>
   </MenuItem>
</Menu>

在您的示例中，只需将弹出颜色更改为红色或透明即可。

Answer 1

不确定这是否是唯一的方法，但您可以覆盖 MenuItem 的 ControlTemplate。基本示例：

        <Menu>
        <MenuItem Header="Item 1">
            <MenuItem.Template>
                <ControlTemplate TargetType="MenuItem">
                    <Border Name="Border" >
                        <Grid>
                            <ContentPresenter Margin="6,3,6,3" ContentSource="Header" RecognizesAccessKey="True" />
                            <Popup Name="Popup" Placement="Bottom" IsOpen="{TemplateBinding IsSubmenuOpen}" AllowsTransparency="True" Focusable="False" PopupAnimation="Fade">
                                <Border Name="SubmenuBorder" SnapsToDevicePixels="True" Background="LightGray" BorderBrush="Transparent" BorderThickness="1" >
                                    <StackPanel IsItemsHost="True" KeyboardNavigation.DirectionalNavigation="Cycle" />
                                </Border>
                            </Popup>
                        </Grid>
                    </Border>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsSuspendingPopupAnimation" Value="true">
                            <Setter TargetName="Popup" Property="PopupAnimation" Value="None"/>
                        </Trigger>
                        <Trigger Property="IsHighlighted" Value="true">
                            <Setter TargetName="Border" Property="Background" Value="LightGray"/>
                            <Setter TargetName="Border" Property="BorderBrush" Value="Transparent"/>
                            <Setter Property="Foreground" Value="Firebrick" />
                        </Trigger>
                        <Trigger  Property="IsHighlighted" Value="False">
                            <Setter Property="Foreground" Value="Black" />
                        </Trigger>
                        <Trigger SourceName="Popup" Property="Popup.AllowsTransparency" Value="True">
                            <Setter TargetName="SubmenuBorder" Property="CornerRadius" Value="0,0,4,4"/>
                            <Setter TargetName="SubmenuBorder" Property="Padding" Value="0,0,0,3"/>
                        </Trigger>
                        <Trigger Property="IsEnabled" Value="False">
                            <Setter Property="Foreground" Value="DarkGray"/>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </MenuItem.Template>
            <MenuItem Header="Sub 1a" />
            <MenuItem Header="Sub 1b" />
        </MenuItem>
    </Menu>

您现在可以单独访问组件部分和样式。