WPF分层DataGrid第二列选中行背景不生效问题求助

问题出在第二列（Device列）的自定义DataGridCell样式里，两个关键原因导致选中时背景不变化：

• 硬编码设置了Background="White"，直接覆盖了DataGrid默认的选中背景色逻辑
• 自定义的ControlTemplate没有添加响应IsSelected状态的触发器，无法在选中时切换背景

修复步骤： #

1. 移除CellStyle里固定的Background设置
2. 在ControlTemplate的Triggers中添加选中状态的触发规则，同步背景色

修改后的第二列CellStyle代码： #

<DataGridTextColumn.CellStyle>
    <Style TargetType="DataGridCell">
        <!-- 移除硬编码的Background="White" -->
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="DataGridCell">
                    <!-- 给外层容器绑定Background，确保选中时能继承状态色 -->
                    <StackPanel Orientation="Horizontal" Background="{TemplateBinding Background}">
                        <ToggleButton x:Name="Expander" 
                                      Margin="{Binding Level,Converter={StaticResource IndentBasedOnLevel}}"
                                      IsChecked="{Binding Path=IsExpanded, UpdateSourceTrigger=PropertyChanged}" ClickMode="Press">
                            <ToggleButton.Style>
                                <Style TargetType="{x:Type ToggleButton}">
                                    <Setter Property="Focusable" Value="False"/>
                                    <Setter Property="Width" Value="19"/>
                                    <Setter Property="Height" Value="13"/>
                                    <Setter Property="Template">
                                        <Setter.Value>
                                            <ControlTemplate TargetType="{x:Type ToggleButton}">
                                                <Border Width="19" Height="13" Background="Transparent">
                                                    <Border Width="11" Height="11"
                                                          BorderThickness="0"
                                                          BorderBrush="#FF7898B5"
                                                          CornerRadius="1"
                                                          SnapsToDevicePixels="true">                                                                             
                                                        <Path x:Name="ExpandPath"
                                                        Margin="1,1,1,1"
                                                        Fill="Black"
                                                        Data="M 0 0 L 9 5 L 0 9 Z"/>
                                                    </Border>
                                                </Border>
                                                <ControlTemplate.Triggers>
                                                    <Trigger Property="IsChecked"
                                                        Value="True">
                                                        <Setter Property="RenderTransform"
                                                            TargetName="ExpandPath">
                                                            <Setter.Value>
                                                                <RotateTransform Angle="180"
                                                                 CenterY="3"
                                                                 CenterX="3" />
                                                            </Setter.Value>
                                                        </Setter>
                                                        <Setter Property="Fill"
                                                            TargetName="ExpandPath"
                                                            Value="Black" />
                                                        <Setter Property="Data"
                                                        TargetName="ExpandPath"
                                                        Value="M 0 7 L 7 0 L 0 0 Z"/>
                                                    </Trigger>
                                                </ControlTemplate.Triggers>
                                            </ControlTemplate>
                                        </Setter.Value>
                                    </Setter>
                                </Style>
                            </ToggleButton.Style>
                        </ToggleButton>
                        <ContentPresenter Content="{TemplateBinding Content}" />
                    </StackPanel>
                    <ControlTemplate.Triggers>
                        <DataTrigger Binding="{Binding HasChildren}" Value="False">
                            <Setter TargetName="Expander" Property="Visibility" Value="Hidden"/>
                        </DataTrigger>
                        <!-- 添加选中状态触发器，同步系统高亮色 -->
                        <Trigger Property="IsSelected" Value="True">
                            <Setter Property="Background" Value="{StaticResource {x:Static SystemColors.HighlightBrushKey}}"/>
                            <!-- 可选：修改选中时的文字颜色，确保可读性 -->
                            <Setter Property="Foreground" Value="White"/>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</DataGridTextColumn.CellStyle>

注：给StackPanel绑定Background="{TemplateBinding Background}"，能让选中时的背景色传递到整个单元格容器，确保视觉效果统一。行/交替行的默认背景色逻辑会自动生效，无需额外设置。

内容的提问来源于stack exchange，提问作者davecove