如何使用Key.Down在ListViews之间导航项目

我的情况如下：

<ListView ItemsSource={Binding TestList}>
    <ListView.ItemTemplate>
        <DataTemplate>
            <Expander Header="{Binding Key, BindingMode=OneWay}">
                <Expander.Content>
                    <ListView ItemsSource={Binding Value}>
                        <ListView.ItemContainerStyle>
                            <Style TargetType = {ListViewItem}>
                                <Setter Property = "IsSelected" Value={Binding IsSelected}/>
                            </Style>
                        </ListView.ItemContainerStyle>
                    </ListView>
                </Expander.Content>
            </Expander>
        </DataTemplate>
    </ListView.ItemTemplate>
</ListView>

测试清单：

Dictionary<string,ObservableCollection<Test>> TestList;

测试：

class Test : NotificationObject
{
    public string Name { get; set;}

    private bool isSelected;
    public bool IsSelected
    {
        if( value != isSelected )
        {
            isSelected = value;
            RaisePropertyChanged("IsSelected");
        }
    }
}   

内部的ListView SelectionMode是Single，我可以使用键盘上和下按钮浏览ListView中的项目。有没有一种方法可以实现此方案：当焦点位于ListView的最后一项上时，请按向下键，焦点将位于下一个ListView的第一项上；如果焦点位于下一个ListView的最后一项上，则将焦点移到下一个ListView。当焦点位于ListView的第一项上时，按向上键，焦点位于上一个ListView的最后一项。

有人可以帮忙吗？

解决方案

public static List<T> FindVisualChildren<T>(DependencyObject depObj) where T : DependencyObject
        {
            List<T> list = new List<T>();
            if (depObj != null)
            {
                for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
                {
                    DependencyObject child = VisualTreeHelper.GetChild(depObj, i);
                    if (child != null && child is T)
                    {
                        list.Add((T)child);
                    }

                    List<T> childItems = FindVisualChildren<T>(child);
                    if (childItems != null && childItems.Count() > 0)
                    {
                        foreach (var item in childItems)
                        {
                            list.Add(item);
                        }
                    }
                }
            }
            return list;
        }

        private void ListView_PreviewKeyDown(object sender, KeyEventArgs e)
        {
            ListView currentListView = sender as ListView;

            List<ListView> listviews = FindVisualChildren<ListView>(ModulesListView);

            int currentListViewIndex = listviews.IndexOf(currentListView);

            // If the press key is Down and the selected item is the last one
            if (Keyboard.IsKeyDown(Key.Down)&& currentListView.SelectedIndex + 1 == currentListView.Items.Count)
            {               
                if (currentListViewIndex + 1 < listviews.Count)
                {
                    // Get next ListView
                    var nextListView = listviews.ElementAt(currentListViewIndex + 1);

                    if (nextListView.Items != null && nextListView.Items.Count > 0)
                    {
                        ListViewItem item = nextListView.ItemContainerGenerator.ContainerFromIndex(0) as ListViewItem;
                        item.Focus();
                        item.IsSelected = true;
                        e.Handled = true;
                    }
                }


            }
            else if (Keyboard.IsKeyDown(Key.Up)&& currentListView.SelectedIndex == 0)
            {
                if (currentListViewIndex > 0)
                {
                    var previousListView = listviews.ElementAt(currentListViewIndex - 1);

                    if (previousListView.Items != null && previousListView.Items.Count > 0)
                    {                                              
                        ListViewItem item = previousListView.ItemContainerGenerator.ContainerFromIndex(previousListView.Items.Count - 1) as ListViewItem;
                        item.Focus();
                        item.IsSelected = true;
                        e.Handled = true;
                    }
                }

            }

        }