C# WPF - 悬停时的自定义菜单项背景答案

【问题标题】：C# WPF - Custom Menu Item Background on HoverC# WPF - 悬停时的自定义菜单项背景
【发布时间】：2019-04-22 22:07:15
【问题描述】：

如何在悬停自定义菜单项时更改其背景？我更改了背景属性，但它没有改变，它保持默认的蓝色。我还尝试更改悬停时的触发器样式，但同样没有帮助，它被忽略了。

这个想法是悬停菜单项，然后应该出现自定义颜色而不是默认的蓝色。

代码如下：

    <Style TargetType="{x:Type Menu}" x:Key="TopbarMenu" BasedOn="{StaticResource BaseStyle}">
    <Setter Property="WindowChrome.IsHitTestVisibleInChrome" Value="True"/>
    <Setter Property="Background" Value="Transparent"/>
    <Setter Property="Foreground" Value="{StaticResource WhiteBrush}"/>
    <Setter Property="BorderThickness" Value="0"/>
    <Setter Property="HorizontalAlignment" Value="Center"/>
    <Setter Property="VerticalAlignment" Value="Center"/>
</Style>
<Style TargetType="{x:Type MenuItem}" x:Key="DropdownMenuButton" BasedOn="{StaticResource BaseStyle}">
    <Setter Property="TextOptions.TextFormattingMode" Value="Display"/>
    <Setter Property="BorderThickness" Value="0"/>
    <Setter Property="Margin" Value="6 0 6 0"/>
</Style>

我认为它与模板有关，但我对模板不是很胜任，我可能从根本上错了，问题可能出在其他问题上。

【问题讨论】：

这不是直接重复，但您可以通过查看以下问题找到答案：How to set MouseOver event/trigger for border in XAML?
不是重复的，这是两个不同的问题。这里一个简单的背景属性更改或简单的样式触发器是不够的。

标签： c# wpf

【解决方案1】：

这就是我的做法……非常适合我：

<ControlTemplate TargetType="{x:Type MenuItem}" x:Key="MenuItemTemplate">
    <Border x:Name="Border" Padding="10,5,10,5" BorderThickness="0" Margin="0">
        <ContentPresenter ContentSource="Header" x:Name="HeaderHost" RecognizesAccessKey="True" />
    </Border>
    <ControlTemplate.Triggers>
        <Trigger Property="IsHighlighted" Value="true">
            <Setter Property="Background" TargetName="Border" Value="Blue"/>
        </Trigger>
    </ControlTemplate.Triggers>
</ControlTemplate>

并用于：

<MenuItem Template="{StaticResource MenuItemTemplate}" Header="test" />

[编辑]

根据要求，这里有一些东西可以正确支持子菜单：

<ControlTemplate TargetType="MenuItem" x:Key="rootMenuItem">
    <Border x:Name="templateRoot" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" SnapsToDevicePixels="True">
        <Grid VerticalAlignment="Center">
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="Auto"/>
                <ColumnDefinition Width="Auto"/>
            </Grid.ColumnDefinitions>
            <ContentPresenter x:Name="Icon" Content="{TemplateBinding Icon}" ContentSource="Icon" HorizontalAlignment="Center" Height="16" Margin="3" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="Center" Width="16"/>
            <Path x:Name="GlyphPanel" Data="F1M10,1.2L4.7,9.1 4.5,9.1 0,5.2 1.3,3.5 4.3,6.1 8.3,0 10,1.2z" Fill="{TemplateBinding Foreground}" FlowDirection="LeftToRight" Margin="3" Visibility="Collapsed" VerticalAlignment="Center"/>
            <ContentPresenter ContentTemplate="{TemplateBinding HeaderTemplate}" Content="{TemplateBinding Header}" Grid.Column="1" ContentStringFormat="{TemplateBinding HeaderStringFormat}" ContentSource="Header" Margin="{TemplateBinding Padding}" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
            <Popup x:Name="PART_Popup" AllowsTransparency="True" Focusable="False" IsOpen="{Binding IsSubmenuOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{DynamicResource {x:Static SystemParameters.MenuPopupAnimationKey}}" Placement="Bottom">
                <Border x:Name="SubMenuBorder" BorderBrush="#FF999999" BorderThickness="1" Background="#FFF0F0F0" Padding="2">
                    <ScrollViewer x:Name="SubMenuScrollViewer" Style="{DynamicResource {ComponentResourceKey ResourceId=MenuScrollViewer, TypeInTargetAssembly={x:Type FrameworkElement}}}">
                        <Grid RenderOptions.ClearTypeHint="Enabled">
                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
                                <Rectangle x:Name="OpaqueRect" Fill="{Binding Background, ElementName=SubMenuBorder}" Height="{Binding ActualHeight, ElementName=SubMenuBorder}" Width="{Binding ActualWidth, ElementName=SubMenuBorder}"/>
                            </Canvas>
                            <Rectangle Fill="#FFD7D7D7" HorizontalAlignment="Left" Margin="29,2,0,2" Width="1"/>
                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Cycle" Grid.IsSharedSizeScope="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" KeyboardNavigation.TabNavigation="Cycle"/>
                        </Grid>
                    </ScrollViewer>
                </Border>
            </Popup>
        </Grid>
    </Border>
    <ControlTemplate.Triggers>
        <Trigger Property="IsSuspendingPopupAnimation" Value="True">
            <Setter Property="PopupAnimation" TargetName="PART_Popup" Value="None"/>
        </Trigger>
        <Trigger Property="Icon" Value="{x:Null}">
            <Setter Property="Visibility" TargetName="Icon" Value="Collapsed"/>
        </Trigger>
        <Trigger Property="IsChecked" Value="True">
            <Setter Property="Visibility" TargetName="GlyphPanel" Value="Visible"/>
            <Setter Property="Visibility" TargetName="Icon" Value="Collapsed"/>
        </Trigger>
        <Trigger Property="IsHighlighted" Value="True">
            <Setter Property="Background" TargetName="templateRoot" Value="BLUE"/>
            <Setter Property="BorderBrush" TargetName="templateRoot" Value="#FF26A0DA"/>
        </Trigger>
        <Trigger Property="IsEnabled" Value="False">
            <Setter Property="TextElement.Foreground" TargetName="templateRoot" Value="#FF707070"/>
            <Setter Property="Fill" TargetName="GlyphPanel" Value="#FF707070"/>
        </Trigger>
        <Trigger Property="CanContentScroll" SourceName="SubMenuScrollViewer" Value="False">
            <Setter Property="Canvas.Top" TargetName="OpaqueRect" Value="{Binding VerticalOffset, ElementName=SubMenuScrollViewer}"/>
            <Setter Property="Canvas.Left" TargetName="OpaqueRect" Value="{Binding HorizontalOffset, ElementName=SubMenuScrollViewer}"/>
        </Trigger>
    </ControlTemplate.Triggers>
</ControlTemplate>



<Style TargetType="MenuItem">
    <Setter Property="Template">
        <Setter.Value>

            <ControlTemplate TargetType="{x:Type MenuItem}">
                <Border x:Name="templateRoot" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" SnapsToDevicePixels="True">
                    <Grid Margin="-1">
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition MinWidth="22" SharedSizeGroup="MenuItemIconColumnGroup" Width="Auto"/>
                            <ColumnDefinition Width="13"/>
                            <ColumnDefinition Width="*"/>
                            <ColumnDefinition Width="30"/>
                            <ColumnDefinition SharedSizeGroup="MenuItemIGTColumnGroup" Width="Auto"/>
                            <ColumnDefinition Width="20"/>
                        </Grid.ColumnDefinitions>
                        <ContentPresenter x:Name="Icon" Content="{TemplateBinding Icon}" ContentSource="Icon" HorizontalAlignment="Center" Height="16" Margin="3" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="Center" Width="16"/>
                        <Border x:Name="GlyphPanel" BorderBrush="#FF26A0DA" BorderThickness="1" Background="#3D26A0DA" Height="22" Margin="-1,0,0,0" Visibility="Hidden" VerticalAlignment="Center" Width="22">
                            <Path x:Name="Glyph" Data="F1M10,1.2L4.7,9.1 4.5,9.1 0,5.2 1.3,3.5 4.3,6.1 8.3,0 10,1.2z" Fill="#FF212121" FlowDirection="LeftToRight" Height="11" Width="9"/>
                        </Border>
                        <ContentPresenter ContentTemplate="{TemplateBinding HeaderTemplate}" Content="{TemplateBinding Header}" Grid.Column="2" ContentStringFormat="{TemplateBinding HeaderStringFormat}" ContentSource="Header" HorizontalAlignment="Left" Margin="{TemplateBinding Padding}" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="Center"/>
                        <TextBlock Grid.Column="4" Margin="{TemplateBinding Padding}" Opacity="0.7" Text="{TemplateBinding InputGestureText}" VerticalAlignment="Center"/>
                        <Path x:Name="RightArrow" Grid.Column="5" Data="M0,0L4,3.5 0,7z" Fill="#FF212121" HorizontalAlignment="Left" Margin="10,0,0,0" VerticalAlignment="Center"/>
                        <Popup x:Name="PART_Popup" AllowsTransparency="True" Focusable="False" HorizontalOffset="-2" IsOpen="{Binding IsSubmenuOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{DynamicResource {x:Static SystemParameters.MenuPopupAnimationKey}}" Placement="Right" VerticalOffset="-3">
                            <Border x:Name="SubMenuBorder" BorderBrush="#FF999999" BorderThickness="1" Background="#FFF0F0F0" Padding="2">
                                <ScrollViewer x:Name="SubMenuScrollViewer" Style="{DynamicResource {ComponentResourceKey ResourceId=MenuScrollViewer, TypeInTargetAssembly={x:Type FrameworkElement}}}">
                                    <Grid RenderOptions.ClearTypeHint="Enabled">
                                        <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
                                            <Rectangle x:Name="OpaqueRect" Fill="{Binding Background, ElementName=SubMenuBorder}" Height="{Binding ActualHeight, ElementName=SubMenuBorder}" Width="{Binding ActualWidth, ElementName=SubMenuBorder}"/>
                                        </Canvas>
                                        <Rectangle Fill="{DynamicResource {x:Static SystemColors.ControlDarkBrushKey}}" HorizontalAlignment="Left" Margin="29,2,0,2" Width="1"/>
                                        <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Cycle" Grid.IsSharedSizeScope="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" KeyboardNavigation.TabNavigation="Cycle"/>
                                    </Grid>
                                </ScrollViewer>
                            </Border>
                        </Popup>
                    </Grid>
                </Border>
                <ControlTemplate.Triggers>
                    <Trigger Property="IsSuspendingPopupAnimation" Value="True">
                        <Setter Property="PopupAnimation" TargetName="PART_Popup" Value="None"/>
                    </Trigger>
                    <Trigger Property="Icon" Value="{x:Null}">
                        <Setter Property="Visibility" TargetName="Icon" Value="Collapsed"/>
                    </Trigger>
                    <Trigger Property="IsChecked" Value="True">
                        <Setter Property="Visibility" TargetName="GlyphPanel" Value="Visible"/>
                        <Setter Property="Visibility" TargetName="Icon" Value="Collapsed"/>
                    </Trigger>
                    <Trigger Property="IsHighlighted" Value="True">
                        <Setter Property="Background" TargetName="templateRoot" Value="BLUE"/>
                        <Setter Property="BorderBrush" TargetName="templateRoot" Value="#FF26A0DA"/>
                    </Trigger>
                    <Trigger Property="IsEnabled" Value="False">
                        <Setter Property="TextElement.Foreground" TargetName="templateRoot" Value="#FF707070"/>
                        <Setter Property="Fill" TargetName="Glyph" Value="#FF707070"/>
                        <Setter Property="Fill" TargetName="RightArrow" Value="#FF707070"/>
                    </Trigger>
                    <Trigger Property="CanContentScroll" SourceName="SubMenuScrollViewer" Value="False">
                        <Setter Property="Canvas.Top" TargetName="OpaqueRect" Value="{Binding VerticalOffset, ElementName=SubMenuScrollViewer}"/>
                        <Setter Property="Canvas.Left" TargetName="OpaqueRect" Value="{Binding HorizontalOffset, ElementName=SubMenuScrollViewer}"/>
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

以及使用测试：

<Menu HorizontalAlignment="Center" VerticalAlignment="Center">
    <MenuItem Header="test" Template="{StaticResource rootMenuItem}">
        <MenuItem Header="test" >
            <MenuItem Header="test">
                <MenuItem Header="test">
                    <MenuItem Header="test">
                        <MenuItem Header="test">
                            <MenuItem Header="test" />
                            <MenuItem Header="test" />
                        </MenuItem>
                        <MenuItem Header="test" />
                    </MenuItem>
                    <MenuItem Header="test" />
                </MenuItem>
                <MenuItem Header="test" />
            </MenuItem>
            <MenuItem Header="test">
                <MenuItem Header="test">
                    <MenuItem Header="test" />
                    <MenuItem Header="test" />
                </MenuItem>
                <MenuItem Header="test">
                    <MenuItem Header="test">
                        <MenuItem Header="test" />
                        <MenuItem Header="test" />
                    </MenuItem>
                    <MenuItem Header="test" />
                </MenuItem>
            </MenuItem>
        </MenuItem>
    </MenuItem>
    <MenuItem Header="test" Template="{StaticResource rootMenuItem}">
        <MenuItem Header="test">
            <MenuItem Header="test" />
            <MenuItem Header="test" />
        </MenuItem>
    </MenuItem>
</Menu>

请注意，根项目除了子项目之外还有另一个模板！在这个演示中，它使用根元素的静态模板绑定来完成，但在实际用例中，您可以使用如下样式选择器来完成此操作：

<Style TargetType="{x:Type MenuItem}" x:Key="{x:Type MenuItem}">
    <Setter Property="OverridesDefaultStyle" Value="True"/>
    <Style.Triggers>
        <Trigger Property="Role" Value="SubmenuHeader">
            <Setter Property="Template" Value="{StaticResource {x:Static MenuItem.SubmenuHeaderTemplateKey}}"/>
        </Trigger>
        <Trigger Property="Role" Value="SubmenuItem">
            <Setter Property="Template" Value="{StaticResource {x:Static MenuItem.SubmenuItemTemplateKey}}"/>
        </Trigger>
    </Style.Triggers>
</Style>

[/EDIT]

[EDIT2] 要使箭头消失，您需要如上所述的 StyleSelector。假设您有两种样式名为“MenuItemWithChildren”和“MenuItemWithoutChildren”，则必须实现此类

class ItemStyleSelector : StyleSelector
{
    public override Style SelectStyle(object item, DependencyObject container)
    {
        if(item is MenuItem mItem)
        {
            if(mItem.Items.Count > 0)
            {
                return App.Current.Resources["MenuItemWithChildren"] as Style;
            }
            else
            {
                return App.Current.Resources["MenuItemWithoutChildren"] as Style;
            }
        }

        return base.SelectStyle(item, container);
    }
}

那么你必须为每个项目定义两个不同的样式和模板，有和没有子项： 重要提示：这些必须在 app.xaml 或链接在那里的一些资源字典中定义，否则 ItemStyleSelector 类将找不到它们。例如。 Window.Resources 将找不到。

<Style TargetType="MenuItem" x:Key="MenuItemWithChildren">
    <Setter Property="ItemContainerStyleSelector" Value="{StaticResource ItemStyleSelector}" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type MenuItem}">
                [Your Template goes here]
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>
<Style TargetType="MenuItem" x:Key="MenuItemWithoutChildren">
    <Setter Property="ItemContainerStyleSelector" Value="{StaticResource ItemStyleSelector}" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type MenuItem}">
                [Your Template goes here]
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

还有您的 Styleselctor 本身和菜单项的默认样式

<local:ItemStyleSelector x:Key="ItemStyleSelector" />
<Style TargetType="MenuItem">
    <Setter Property="ItemContainerStyleSelector" Value="{StaticResource ItemStyleSelector}" />
</Style>

并在菜单中声明选择：

<Menu ItemContainerStyleSelector="{StaticResource ItemStyleSelector}">
    <MenuItem Header="test" Template="{StaticResource rootMenuItem}">
        <MenuItem Header="test">
            <MenuItem Header="test" />
            <MenuItem Header="test" />
        </MenuItem>
    </MenuItem>
</Menu>

[/EDIT2]

【讨论】：

非常感谢，它确实有效。它快吗？是否考虑了性能？
从未做过任何大型性能测试，但据我所知，ControlTemplates 和 Triggers 是在 WPF 环境中使用的方法......我在多个基于 Tray-Icon 的应用程序中为我们的 6 位开发人员使用它团队，我们在菜单方面从未遇到任何性能问题（在某些情况下是多级级联）......
好的，太好了！顺便说一句，我不能只使用 Style="{StaticResource DropdownMenuButton}" 它似乎对我有用，是一样的吗？从我猜你的绑定模板，我的绑定整个样式
知道为什么该菜单中的子项没有出现吗？当我从菜单中单击一个项目时，甚至没有下拉菜单，这是为什么呢？
刚刚创建了一个修复错误的拉取请求。很简单；）