WPF, Combobox внутри Listview

<Window x:Class="Test.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="461.2" Width="680.2">
    <Grid>


        <ListView 
                ItemsSource="{Binding Path=TableWithData}" 
                Name="ListView_Brands" 
                SelectionMode="Single" 
                ScrollViewer.HorizontalScrollBarVisibility="Disabled" 
                ScrollViewer.VerticalScrollBarVisibility="Visible" MaxHeight="600" >
            <ListView.View>
                <GridView>
                    <GridViewColumn Header="Название бренда" DisplayMemberBinding="{Binding Path=BrandName}" Width="150" />
                    <GridViewColumn Header="Страна" DisplayMemberBinding="{Binding Path=BrandCountry}" Width="100" />

                    <!--вот эта колонка должна быть с выпадающим списком-->
                    <GridViewColumn Header="Группа" DisplayMemberBinding="{Binding Path=BrandGroup}" Width="200" />

                    <!--попытка создать выпадающий список-->
                    <GridViewColumn Header="Группа 2" >
                        <GridViewColumn.CellTemplate>
                            <DataTemplate>
                                <ComboBox Width="160" SelectedValue="{Binding Path=BrandGroup}">
                                    <ComboBoxItem Content="Russian brands" />
                                    <ComboBoxItem Content="Foreign brands" />
                                </ComboBox>
                            </DataTemplate>
                        </GridViewColumn.CellTemplate>
                    </GridViewColumn>

                </GridView>
            </ListView.View>
        </ListView>



    </Grid>
</Window>

using System.Collections.ObjectModel;
using System.Windows;
using System.ComponentModel;

namespace Test
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            // Ставим источник данных для формы. Сам класс ViewModel чуть ниже.
            this.DataContext = new ViewModel();
        }
    }



    /// <summary>
    /// Источник данных для формы
    /// </summary>
    class ViewModel : ViewModelBase
    {
        public ObservableCollection<ListViewRow> _Source;

        public ViewModel()
        {
            _Source = new ObservableCollection<ListViewRow>();
            _Source.Add(new ListViewRow { BrandName = "Dodge", BrandCountry = "USA", BrandGroup = "Foreign brands" });
            _Source.Add(new ListViewRow { BrandName = "FAW", BrandCountry = "China", BrandGroup = "Foreign brands" });
            _Source.Add(new ListViewRow { BrandName = "Ferrari", BrandCountry = "Italy", BrandGroup = "Foreign brands" });
            _Source.Add(new ListViewRow { BrandName = "Fiat", BrandCountry = "Italy", BrandGroup = "Foreign brands" });
            _Source.Add(new ListViewRow { BrandName = "VAZ", BrandCountry = "Russia", BrandGroup = "Russian brands" });
            _Source.Add(new ListViewRow { BrandName = "Kamaz", BrandCountry = "Russia", BrandGroup = "Russian brands" });
        }

        /// <summary>
        /// Свойство - будет ItemsSource для ListView
        /// </summary>
        public ObservableCollection<ListViewRow> TableWithData
        {
            get { return _Source; }
        }

    }


    /// <summary>
    /// Одна строка с данными
    /// </summary>
    public class ListViewRow
    {
        public string BrandName { get; set; }
        public string BrandCountry { get; set; }
        public string BrandGroup { get; set; }
    }


    /// <summary>
    /// Вспомогательный класс для создания всех ViewModel
    /// </summary>
    public class ViewModelBase : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;
        protected void NotifyPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }




}