如何在listview中的分组的最后一项后添加填充？(xaml)

<ListView ItemsSource="{Binding Source={StaticResource MyCollectionViewSource}}">
    <ListView.GroupStyle>
        <GroupStyle>
            <GroupStyle.ContainerStyle>
                <Style TargetType="GroupItem">
                    <Style.Triggers>
                        <DataTrigger Binding="{Binding Items/IsLastItem}" Value="True">
                            <Setter Property="Template">
                                <Setter.Value>
                                    <ControlTemplate TargetType="GroupItem">
                                        <StackPanel>
                                            <ItemsPresenter />
                                            <TextBlock Text="填充项" />
                                        </StackPanel>
                                    </ControlTemplate>
                                </Setter.Value>
                            </Setter>
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
            </GroupStyle.ContainerStyle>
        </GroupStyle>
    </ListView.GroupStyle>
    <ListView.ItemTemplate>
        <!-- 定义 ListView 的项模板 -->
    </ListView.ItemTemplate>
</ListView>