扩展器标头组描述另一个控件中的额外摘要

Question

我无法在另一个控件中添加包含组描述的摘要，该控件实际上与wpf中的组描述绑定相关联。

摘要可以作为Cluster中的属性和Name一起使用，我想在扩展程序头中显示所有值

.cs

using System;
using System.Collections.ObjectModel;
using System.Windows;
using System.Windows.Data;

namespace EmptyGroups
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();

            var clusters = new[]
            {
                new Cluster { valueName = "Front end" , Summary = "Front Summary"},
                new Cluster { valueName = "Middle end" , Summary = "Middle Summary"},
                new Cluster { valueName = "Back end" , Summary = "Back Summary"},
            };

            var collectionView = new ListCollectionView(new[]
            {
                new Server { Cluster = clusters[0], Name = "webshop1" },
                new Server { Cluster = clusters[0], Name = "webshop2" },
                new Server { Cluster = clusters[0], Name = "webshop3" },
                new Server { Cluster = clusters[0], Name = "webshop4" },
                new Server { Cluster = clusters[0], Name = "webshop5" },
                new Server { Cluster = clusters[0], Name = "webshop6" },
                new Server { Cluster = clusters[2], Name = "sql1" },
                new Server { Cluster = clusters[2], Name = "sql2" },
            });

            var groupDescription = new PropertyGroupDescription("Cluster.valueName");

            foreach (var cluster in clusters)
            {
                groupDescription.GroupNames.Add(cluster.valueName);
            }

            collectionView.GroupDescriptions.Add(groupDescription);
            ServersList.ItemsSource = collectionView;

        }

        readonly ObservableCollection<object> Clusters;

        void AddNewCluster_Click(object sender, RoutedEventArgs e)
        {
            Clusters.Add(NewClusterName.Text);
        }
    }

    class Cluster
    {
        public string valueName { get; set; }

        public string Summary { get; set; }
    }

    class Server
    {
        public Cluster Cluster { get; set; }
        public string Name { get; set; }
    }
}

XAML

<Window
    x:Class="EmptyGroups.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Servers by cluster"
    WindowStartupLocation="CenterScreen">

    <DockPanel>

        <WrapPanel DockPanel.Dock="Top" Background="BlanchedAlmond">
            <Label Content="Cluster name:" Margin="10"/>
            <TextBox x:Name="NewClusterName" Text="type new cluster name here" MinWidth="50" BorderThickness="1" Margin="10"/>
            <Button Content="Add cluster" Click="AddNewCluster_Click" Margin="10"/>
        </WrapPanel>

        <ListView x:Name="ServersList">

            <ListView.GroupStyle>
                <GroupStyle HidesIfEmpty="False">
                    <GroupStyle.ContainerStyle>
                        <Style TargetType="GroupItem">
                            <Setter Property="Template">
                                <Setter.Value>
                                    <ControlTemplate TargetType="GroupItem">
                                        <Expander IsExpanded="True">
                                            <Expander.Header>
                                                <TextBlock TextWrapping="Wrap" Margin="0,10,0,5" >
                                                    <Bold><TextBlock Text="{Binding Name}"/></Bold> (<TextBlock Text="{Binding ItemCount}"/> servers) Summary : <TextBlock Text="{Binding Summary}"/>
                                                </TextBlock>
                                            </Expander.Header>
                                            <ItemsPresenter/>
                                        </Expander>
                                    </ControlTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </GroupStyle.ContainerStyle>
                </GroupStyle>
            </ListView.GroupStyle>

            <ListView.View>
                <GridView>
                    <GridViewColumn Header="Server" DisplayMemberBinding="{Binding Name}"/>
                    <GridViewColumn Header="Cluster" DisplayMemberBinding="{Binding Cluster.Name}"/>
                </GridView>
            </ListView.View>
        </ListView>
    </DockPanel>
</Window>

screen shot for current code

expected screen shot