打开上下文菜单->右键单击触发 ViewModel 中的 LeftClick 命令

Question

我有一个 ContextMenu 绑定到一个显示 TreeView 结构的 HierarchicalDataTemplate。 ContextMenu 也是一个 HierarchicalDataTemplate，它通过 MenuItemViewModels 的 ObservableCollection 获取其结构。

我的问题是，当运行程序时，右键单击已打开的 ContextMenu 会意外触发 MenuItem 上的 LeftClick - 为什么会这样？我错过了什么？我无法在代码中找到错误，希望能提供任何帮助。

TreeView 的 XAML：

<HierarchicalDataTemplate x:Key="TreeHierarchicalDataTemplate" DataType="{x:Type model:TreeNodeBaseViewModel}" ItemsSource="{Binding Path=SubItems, UpdateSourceTrigger=PropertyChanged}" ItemContainerStyle="{StaticResource  MenuItemTemplateItemContainerStyle}">
<!--...-->
</HierarchicalDataTemplate>

<Style x:Key="MenuItemTemplateItemContainerStyle" TargetType="{x:Type TreeViewItem}">
    <Setter Property="ContextMenu" Value="{DynamicResource MenuItemContextMenu}"/>
    <Setter Property="IsEnabled" Value="{Binding IsEnabled}"/>
    <Setter Property="AllowDrop" Value="{Binding IsDropAllowed}"/>
    <Setter Property="IsExpanded" Value="{Binding IsExpanded, Mode=TwoWay}"/>
    <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}"/>
    <Setter Property="Tag" Value="{Binding}"/>
    <Style.Triggers>
        <DataTrigger Binding="{Binding Path=IsVisible}" Value="False">
            <Setter Property="Visibility" Value="Collapsed"/>
        </DataTrigger>
        <Trigger Property="beh:TreeNodeMouseOver.IsMouseDirectlyOverItem" Value="True">
            <Setter Property="Background" Value="AliceBlue" />
        </Trigger>
    </Style.Triggers>
</Style>

ContextMenu 的 XAML：

<ContextMenu x:Key="MenuItemContextMenu" ItemsSource="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=Window}, Path=TreeViewModel.MenuItems, UpdateSourceTrigger=PropertyChanged}">
    <ContextMenu.ItemTemplate>
        <HierarchicalDataTemplate DataType="{x:Type model:MenuItemBaseViewModel}" ItemsSource="{Binding Path=SubItems, UpdateSourceTrigger=PropertyChanged}">
            <TextBlock Text="{Binding Header}"/>
        </HierarchicalDataTemplate>
    </ContextMenu.ItemTemplate>
    <ContextMenu.ItemContainerStyle>
        <Style TargetType="MenuItem">
            <Setter Property="ToolTip" Value="{Binding ToolTip}"/>
            <Setter Property="IsHitTestVisible" Value="True"/>
            <Setter Property="IsEnabled" Value="{Binding IsEnabled}"/>
            <Setter Property="Command" Value="{Binding MouseLeftButtonDownCommand}"/> <!--LeftClick is bound to ViewModel here, but RightClick is not even defined anywhere in MenuItem or ViewModel-->
            <Style.Triggers>
                <DataTrigger Binding="{Binding VisibleSubItems}" Value="0">
                    <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="20"/>
                                            <ColumnDefinition SharedSizeGroup="MenuItemIGTColumnGroup" Width="Auto"/>
                                            <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"/>
                                        <Border x:Name="GlyphPanel" BorderBrush="#FF26A0DA" BorderThickness="1" Background="#3D26A0DA" ClipToBounds="False" HorizontalAlignment="Center" 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="10"/>
                                        </Border>
                                        <ContentPresenter x:Name="menuHeaderContainer" 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 x:Name="menuGestureText" Grid.Column="4" Margin="{TemplateBinding Padding}" Opacity="0.7" Text="{TemplateBinding InputGestureText}" VerticalAlignment="Center"/>
                                        <Button Grid.Column="5" Margin="2" Command="{Binding EditCommand}" Visibility="{Binding IsEditVisible, Converter={StaticResource BooleanToVisibilityConverter}}" Background="Transparent" BorderThickness="0">
                                            <iconPacks:PackIconMaterialLight Width="14" Height="14" Foreground="Black" HorizontalAlignment="Center" VerticalAlignment="Center" Kind="Cog" />
                                        </Button>
                                        <Button Grid.Column="6" Margin="2" Command="{Binding HelpCommand}" Visibility="{Binding IsInfoVisible, Converter={StaticResource BooleanToVisibilityConverter}}" Background="Transparent" BorderThickness="0">
                                            <iconPacks:PackIconMaterial  Width="14" Height="14" Foreground="Blue" HorizontalAlignment="Center" VerticalAlignment="Center" Kind="InformationOutline" />
                                        </Button>
                                    </Grid>
                                </Border>
                                <ControlTemplate.Triggers>
                                    <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="#3D26A0DA"/>
                                        <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"/>
                                    </Trigger>
                                    <MultiTrigger>
                                        <MultiTrigger.Conditions>
                                            <Condition Property="IsHighlighted" Value="True"/>
                                            <Condition Property="IsEnabled" Value="False"/>
                                        </MultiTrigger.Conditions>
                                        <Setter Property="Background" TargetName="templateRoot" Value="#0A000000"/>
                                        <Setter Property="BorderBrush" TargetName="templateRoot" Value="#21000000"/>
                                    </MultiTrigger>
                                </ControlTemplate.Triggers>
                            </ControlTemplate>
                        </Setter.Value>
                    </Setter>
                </DataTrigger>
                <DataTrigger Binding="{Binding IsVisible}" Value="false">
                    <Setter Property="MenuItem.Visibility" Value="Collapsed"/>
                </DataTrigger>
                <DataTrigger Binding="{Binding PackIcon.IconType}" Value="{x:Type iconPacks:PackIconSimpleIconsKind}">
                    <Setter Property="MenuItem.Icon" Value="{StaticResource Simple}"/>
                </DataTrigger>
                <DataTrigger Binding="{Binding PackIcon.IconType}" Value="{x:Type iconPacks:PackIconEntypoKind}">
                    <Setter Property="MenuItem.Icon" Value="{StaticResource Entypo}"/>
                </DataTrigger>
                <DataTrigger Binding="{Binding PackIcon.IconType}" Value="{x:Type iconPacks:PackIconFontAwesomeKind}">
                    <Setter Property="MenuItem.Icon" Value="{StaticResource FontAwesome}"/>
                </DataTrigger>
                <DataTrigger Binding="{Binding PackIcon.IconType}" Value="{x:Type iconPacks:PackIconMaterialKind}">
                    <Setter Property="MenuItem.Icon" Value="{StaticResource Material}"/>
                </DataTrigger>
                <DataTrigger Binding="{Binding PackIcon.IconType}" Value="{x:Type iconPacks:PackIconMaterialLightKind}">
                    <Setter Property="MenuItem.Icon" Value="{StaticResource MaterialLight}"/>
                </DataTrigger>
                <DataTrigger Binding="{Binding PackIcon.IconType}" Value="{x:Type iconPacks:PackIconModernKind}">
                    <Setter Property="MenuItem.Icon" Value="{StaticResource Modern}"/>
                </DataTrigger>
                <DataTrigger Binding="{Binding PackIcon.IconType}" Value="{x:Type iconPacks:PackIconOcticonsKind}">
                    <Setter Property="MenuItem.Icon" Value="{StaticResource Octicons}"/>
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </ContextMenu.ItemContainerStyle>
    <i:Interaction.Behaviors>
        <beh:EventToCommandBehavior Command="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=Window}, Path=TreeViewModel.ContextMenuOpenedCommand}" Event="Opened" PassArguments="True" />
    </i:Interaction.Behaviors>
</ContextMenu>

Answer 1

这种行为是设计使然。如果您想为您的菜单项单独的左/右键单击处理程序，那么您需要将相应的 MouseBindings 添加到您的 MenuItem InputBindings 集合中。如果您需要以某种风格执行此操作，则可以使用the Attach behavior in this question。

<ContextMenu.ItemContainerStyle>
    <Style TargetType="MenuItem">
        <Setter Property="behaviors:Attach.InputBindings">
            <Setter.Value>
                <InputBindingCollection>
                    <MouseBinding Gesture="LeftClick" Command="{Binding LeftClickCommand}" />
                    <MouseBinding Gesture="RightClick" Command="{Binding RightClickCommand}" />
                </InputBindingCollection>
            </Setter.Value>
        </Setter>
    </Style>
</ContextMenu.ItemContainerStyle>