WPF MVVM中DataGrid的ComboBox列实现交替行背景绑定

我已经修改了ComboBox的Style，将ComboBox内部ToggleButton的Background绑定到ComboBox自身的Background属性（这是让ToggleButton跟随ComboBox背景色的可行方式），相关Style代码如下：

...
<Style x:Key="ComboBoxToggleButton" TargetType="{x:Type ToggleButton}">
...
<Setter Property="Template">
    <Setter.Value>
        <ControlTemplate TargetType="{x:Type ToggleButton}">
            <Border x:Name="templateRoot" BorderBrush="{StaticResource ComboBox.Static.Border}"
                BorderThickness="{TemplateBinding BorderThickness}"
                Background="{TemplateBinding Background}" SnapsToDevicePixels="true"> <!-- 绑定位置 -->
                    <Border x:Name="splitBorder" BorderBrush="Transparent" BorderThickness="1" HorizontalAlignment="Right"
                        Margin="0" SnapsToDevicePixels="true"
                        Width="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}">
                            <Path x:Name="arrow"
                                Data="F1 M 0,0 L 2.667,2.66665 L 5.3334,0 L 5.3334,-1.78168 L 2.6667,0.88501 L0,-1.78168 L0,0 Z"
                                Fill="{StaticResource ComboBox.Static.Glyph}" HorizontalAlignment="Center" Margin="0" VerticalAlignment="Center"/>
                            </Border>
                        </Border>
                        <ControlTemplate.Triggers>
                        ...

此时单独使用<ComboBox Background="Yellow" />可以正常生效，ToggleButton的背景会同步变成黄色。

现在我有一个包含ComboBox列的DataGrid，希望让ComboBox的Background自动跟随DataGrid的交替行颜色，当前代码如下：

<DataGrid AutoGenerateColumns="False" Name="datagrid1"
          Height="auto"
          ItemsSource="{Binding SourceList}"
          SelectedItem="{Binding SelectedSource}"
          BorderThickness="1"
          AlternatingRowBackground="#FFFFFFCC" 
          HorizontalGridLinesBrush="#FFA0A0A0"
          VerticalGridLinesBrush="#FFA0A0A0"
          SelectionUnit="FullRow"
          HeadersVisibility="Column"
          GridLinesVisibility="Horizontal"
          CanUserResizeRows="False"
          VerticalContentAlignment="Center"
          BorderBrush="DarkGray"
          HorizontalAlignment="Stretch">
              <DataGrid.Columns>
                  <DataGridTextColumn Header="NameText" Binding="{Binding NameText}" Width="*"/>
                  <DataGridTemplateColumn Width = "*" Header = "Names">
                      <DataGridTemplateColumn.CellTemplate>
                          <DataTemplate>
                              <ComboBox VerticalContentAlignment = "Center"
                                        ItemsSource = "{Binding DataContext.NamesList, RelativeSource ={RelativeSource Findancestor, AncestorType = { x:Type Window}}}"
                                        SelectedItem="{Binding Name, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
                                        DisplayMemberPath="Name">
                                            <ComboBox.Style>
                                                <Style TargetType="ComboBox" BasedOn="{StaticResource {x:Type ComboBox}}">
                                                    <Setter Property="Background" Value="Yellow"/>
                                                    <Style.Triggers>
                                                        <DataTrigger Binding="{Binding Path=ItemsControl.AlternationIndex, ElementName=datagrid1}" Value="1">
                                                            <Setter Property="Background" Value="#FFFFFFCC"></Setter>
                                                        </DataTrigger>
                                                    </Style.Triggers>
                                                </Style>
                                          </ComboBox.Style>
                              </ComboBox>
                          </DataTemplate>
                      </DataGridTemplateColumn.CellTemplate>
                  </DataGridTemplateColumn>
              </DataGrid.Columns>
</DataGrid>

请问该如何实现让ComboBox背景跟随DataGrid交替行颜色的需求？

当前代码的核心问题是：DataTemplate有独立的命名作用域，无法通过ElementName=datagrid1直接绑定外部DataGrid的AlternationIndex；同时硬写颜色值不够灵活，最好直接绑定DataGrid的AlternatingRowBackground属性。

具体修改步骤如下：

1. 给DataGrid显式添加AlternationCount="2"，确保交替行逻辑正常触发（仅设置AlternatingRowBackground有时不会自动开启交替机制）。
2. 修改ComboBox的Style，通过RelativeSource找到当前所在的DataGridRow来绑定AlternationIndex，同时绑定DataGrid的AlternatingRowBackground属性，避免硬编码颜色值。

修改后的ComboBox.Style代码：

<ComboBox.Style>
    <Style TargetType="ComboBox" BasedOn="{StaticResource {x:Type ComboBox}}">
        <!-- 默认背景色，与DataGrid普通行背景保持一致 -->
        <Setter Property="Background" Value="White"/>
        <Style.Triggers>
            <!-- 绑定当前行的AlternationIndex -->
            <DataTrigger Binding="{Binding AlternationIndex, RelativeSource={RelativeSource AncestorType=DataGridRow}}" Value="1">
                <!-- 绑定DataGrid的交替行背景色 -->
                <Setter Property="Background" Value="{Binding AlternatingRowBackground, RelativeSource={RelativeSource AncestorType=DataGrid}}"/>
            </DataTrigger>
        </Style.Triggers>
    </Style>
</ComboBox.Style>

同时在DataGrid标签中补充AlternationCount属性：

<DataGrid AutoGenerateColumns="False" Name="datagrid1"
          ...
          AlternationCount="2"
          AlternatingRowBackground="#FFFFFFCC" 
          ...>

修改完成后，交替行内的ComboBox会自动继承DataGrid的交替行背景色，普通行则使用默认背景色，同时解决了DataTemplate命名作用域导致的绑定失效问题。

内容的提问来源于stack exchange，提问作者Yannick