我在设置树形视图根节点的背景色时遇到问题。

Question

我有一个绑定到分层数据模板的树视图控件 对于根节点，我必须隐藏扩展器控件，对于后续级别，我必须显示扩展器控件。

我的根节点包含一个切换按钮和文本块控件。 不知何故，我无法为根节点正确设置背景颜色。

Xaml页面：

            <StackPanel Name="Stack2" Margin="0,-20,0,0" Orientation="Horizontal">
                <TreeView x:Name="MainTreeView" HorizontalContentAlignment="Stretch"  Background="{StaticResource White1}"
                              ItemContainerStyle="{StaticResource MyTreeView1}"  BorderThickness="0"   ItemsSource="{Binding RootNodeList}" 
                               HorizontalAlignment="Stretch" Margin="0,20,0,0" VerticalAlignment="Stretch">

                    <TreeView.ItemTemplate>
                        <HierarchicalDataTemplate  ItemContainerStyle="{StaticResource MyTreeView}"  ItemsSource="{Binding ComponentTypesNodes}">
                            <StackPanel Orientation="Vertical">
                                <StackPanel  Name="Stack1" Orientation="Horizontal" HorizontalAlignment="Stretch"  Margin="-20,15,0,0"  Background="{StaticResource White1}">
                                    <ToggleButton Margin="10,0,0,0" Name="Tg1" Template="{Binding ControlTemplate,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" Click="Tg1_Click"/>
                                    <TextBlock  Name="lblName" Margin="30,0,0,0"  Text="{Binding RootNodeName}" Style="{StaticResource TreeViewRootNode}"/>
                                <Grid Name="ItemSelectedIndicator" Grid.ColumnSpan="2"  Grid.Column="0" Background="{StaticResource White6}"
                              Visibility="Collapsed" />
                                </StackPanel>
                                <Separator Margin="0,0,0,0" Height="10" Background="{StaticResource White1}" Width="300"/>
                            </StackPanel>
                            <HierarchicalDataTemplate.ItemTemplate>
                                <HierarchicalDataTemplate  ItemContainerStyle="{StaticResource MyTreeView}"  ItemsSource="{Binding ComponentList}" >
                                    <TextBlock Text="{Binding ComponentType}" HorizontalAlignment="Stretch" Padding="6,6,0,0" Style="{StaticResource TreeViewRootNode}"/>
                                    <HierarchicalDataTemplate.ItemTemplate>
                                        <DataTemplate>
                                            <TextBlock  Text="{Binding ComponentName}" HorizontalAlignment="Stretch" Padding="0,6,0,0" Style="{StaticResource TreeViewRootNode}"/>

                                        </DataTemplate>
                                    </HierarchicalDataTemplate.ItemTemplate>
                                </HierarchicalDataTemplate>
                            </HierarchicalDataTemplate.ItemTemplate>
                        </HierarchicalDataTemplate>
                    </TreeView.ItemTemplate>
                </TreeView>
            </StackPanel>
        <Border Name="BrdPin"  Background="Gray" Margin="-70,-620,30,0" Height="30" Width="30" HorizontalAlignment="Right">
            <ToggleButton Name="TogglePin" Template="{StaticResource Pin}" Click="TogglePin_Click" />
        </Border>

    </StackPanel>

样式页面如下：

<Style TargetType="{x:Type TreeViewItem}" x:Key="MyTreeView">
    <Setter Property="Background" Value="Transparent"/>
    <Setter Property="HorizontalContentAlignment" Value="{Binding HorizontalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}"/>
    <Setter Property="VerticalContentAlignment" Value="{Binding VerticalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}"/>
    <Setter Property="Padding" Value="0,0,0,0"/>
    <Setter Property="Foreground" Value="{StaticResource Gray4}"/>
    <Setter Property="ToggleButton.IsChecked" Value="True"/>
    <Setter Property="FocusVisualStyle" Value="{StaticResource TreeViewItemFocusVisual}"/>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type TreeViewItem}">
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition MinWidth="19" Width="Auto"/>
                        <ColumnDefinition Width="Auto"/>
                        <ColumnDefinition Width="*"/>
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="Auto"/>
                        <RowDefinition/>
                    </Grid.RowDefinitions>
                    <ToggleButton Margin="30,5,0,0" x:Name="Expander" ClickMode="Press" IsChecked="{Binding IsExpanded, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ExpandCollapseToggleStyle}"/>
                    <Border x:Name="Bd"  BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.Column="1" Padding="{TemplateBinding Padding}" SnapsToDevicePixels="true">
                        <ContentPresenter x:Name="PART_Header"  ContentSource="Header" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"  SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" Margin="0,0,0,0"/>
                    </Border>
                    <ItemsPresenter HorizontalAlignment="Stretch" x:Name="ItemsHost" Grid.ColumnSpan="2" Grid.Column="1" Grid.Row="1"/>
                </Grid>
                <ControlTemplate.Triggers>
                    <Trigger Property="IsExpanded" Value="false">
                        <Setter Property="Visibility" TargetName="ItemsHost" Value="Collapsed"/>
                    </Trigger>
                    <Trigger Property="HasItems" Value="false">
                        <Setter Property="Visibility" TargetName="Expander" Value="Hidden"/>
                    </Trigger>
                    <Trigger Property="IsSelected" Value="true">
                        <Setter Property="Background" TargetName="Bd" Value="{StaticResource White6}"/>
                        <Setter Property="TextBlock.Foreground"  Value="{StaticResource Blue}"/>
                        <Setter Property="ToggleButton.IsChecked" Value="True"/>
                    </Trigger>

                    <MultiTrigger>
                        <MultiTrigger.Conditions>
                            <Condition Property="IsSelected" Value="true"/>
                            <Condition Property="IsSelectionActive" Value="false"/>
                        </MultiTrigger.Conditions>
                        <Setter Property="Background" TargetName="Bd" Value="{StaticResource White6}"/>
                        <Setter Property="TextBlock.Foreground" Value="Green"/>
                        <Setter Property="ToggleButton.IsChecked" Value="True"/>
                    </MultiTrigger>

                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
    <Style.Triggers>
        <Trigger Property="VirtualizingStackPanel.IsVirtualizing" Value="true">
            <Setter Property="ItemsPanel">
                <Setter.Value>
                    <ItemsPanelTemplate>
                        <VirtualizingStackPanel/>
                    </ItemsPanelTemplate>
                </Setter.Value>
            </Setter>
        </Trigger>
        <Trigger Property="IsSelected" Value="True">
            <Setter Property="Foreground" Value="{StaticResource Blue}"/>
            <Setter Property="ToggleButton.IsChecked" Value="True"/>
        </Trigger>
    </Style.Triggers>
</Style>

<Style x:Key="ExpandCollapseToggleStyle1" TargetType="{x:Type ToggleButton}">
    <Setter Property="Focusable" Value="False"/>
    <Setter Property="Width" Value="16"/>
    <Setter Property="Height" Value="16"/>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type ToggleButton}">
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

<Style TargetType="{x:Type TreeViewItem}" x:Key="MyTreeView1">

    <Setter Property="Background" Value="Transparent"/>

    <Setter Property="HorizontalContentAlignment" Value="Center"/>
    <Setter Property="VerticalContentAlignment" Value="{Binding VerticalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}"/>
    <Setter Property="Padding" Value="0,0,0,0"/>
    <Setter Property="Foreground" Value="{StaticResource Gray4}"/>
    <Setter Property="Opacity" Value="100"/>
    <Setter Property="FocusVisualStyle" Value="{StaticResource TreeViewItemFocusVisual}"/>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type TreeViewItem}">
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition MinWidth="19" Width="Auto"/>
                        <ColumnDefinition Width="Auto"/>
                        <ColumnDefinition Width="*"/>
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="Auto"/>
                        <RowDefinition/>
                    </Grid.RowDefinitions>
                    <Border x:Name="Bd" VerticalAlignment="Stretch" BorderThickness="0" Background="{TemplateBinding Background}" Grid.Column="1" Padding="{TemplateBinding Padding}" SnapsToDevicePixels="true">
                        <ContentPresenter x:Name="PART_Header" VerticalAlignment="Stretch" ContentSource="Header" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" Margin="0,0,0,0"/>
                    </Border>
                    <ItemsPresenter HorizontalAlignment="Stretch" VerticalAlignment="Stretch" x:Name="ItemsHost" Grid.ColumnSpan="2" Grid.Column="1" Grid.Row="1"/>
                </Grid>
                <ControlTemplate.Triggers>
                    <Trigger Property="IsExpanded" Value="false">
                        <Setter Property="Visibility" TargetName="ItemsHost" Value="Collapsed"/>
                    </Trigger>
                    <Trigger Property="IsSelected" Value="true">
                        <Setter Property="Panel.Background" TargetName="Bd" Value="Red"/>
                        <Setter Property="TextBlock.Foreground"  Value="Green"/>
                        <Setter Property="ToggleButton.IsChecked" Value="True"/>
                    </Trigger>
                    <MultiTrigger>
                        <MultiTrigger.Conditions>
                            <Condition Property="IsSelected" Value="true"/>
                            <Condition Property="IsSelectionActive" Value="false"/>
                        </MultiTrigger.Conditions>
                        <Setter Property="Background" TargetName="Bd" Value="Transparent"/>
                        <Setter Property="TextBlock.Foreground" Value="Green"/>
                        <Setter Property="ToggleButton.IsChecked" Value="True"/>
                    </MultiTrigger>
                    <Trigger Property="IsEnabled" Value="false">
                        <Setter Property="Foreground" Value="Transparent"/>
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
    <Style.Triggers>
        <Trigger Property="VirtualizingStackPanel.IsVirtualizing" Value="true">
            <Setter Property="ItemsPanel">
                <Setter.Value>
                    <ItemsPanelTemplate>
                        <VirtualizingStackPanel/>
                    </ItemsPanelTemplate>
                </Setter.Value>
            </Setter>
        </Trigger>
        <Trigger Property="IsSelected" Value="True">
            <Setter Property="Foreground" Value="{StaticResource Blue}"/>
            <Setter Property="ToggleButton.IsChecked" Value="True"/>
        </Trigger>
    </Style.Triggers>
</Style>`