为什么我的第二个可观察收藏正在更新

我有两个填充了相同类型的项目(项目也是填充了其他类型的对象的可观察集合(。

_TreeViewBase - First ObservableCollection 是包含所有数据的"基础"。

_TVData - Second ObservableCollection 应该只存储"需要"的项目，我也有 TreeView 与 ItemSource 绑定到 TVData。

函数 FillAliasTreeView 仅用于用数据填充_TreeViewBase，所以我不会在此处粘贴代码。

在程序开始时，我将_TreeViewBase分配给LoadSideBar(( 函数中的_TVData，一切都很好。两个 ObservableCollection 都在存储所有数据。

但是当我搜索某些内容时(并且我的 TVData 在 SearchBox_TextChanged(( 中被修改(，那么似乎_TreeViewBase也被修改。

怎么可能？我的代码中是否犯了什么重大错误？

我的类(几乎完整的代码(：

public partial class SideBar : Page, INotifyPropertyChanged
{
    private ObservableCollection<ConnectionModel> _TreeViewBase;
    private ObservableCollection<ConnectionModel> _TVData ;

    public SideBar()
    {
        TreeViewBase = new ObservableCollection<ConnectionModel>( ConnectionUtilities.LoadObservableConnections() ) ;
        TVData       = new ObservableCollection<ConnectionModel>();
        InitializeComponent();

        DataContext = this;
        var loadSideBar = Task.Factory.StartNew( async () => { await LoadSideBar();   } );
        loadSideBar.Wait();
        OnPropertyChanged("TVData");
    }

    public async Task LoadSideBar()
    {
        // this function is used to fill my _TreeViewBase  
        await FillAliasTreeView();
        TVData = TreeViewBase;
        OnPropertyChanged("TVData");
    }
     private async void SearchBox_TextChanged(object sender, TextChangedEventArgs e)
    {
        string newsearchText = SearchBox.Text;
        if ( (newsearchText == "" || newsearchText == "Search..." || newsearchText.Length < 3  )  ) 
        {
            TVData.Clear();
            TVData = null;
            MessageBox.Show( (TVData == null).ToString() + " " + TreeViewBase.Count.ToString());

            TVData = new ObservableCollection<ConnectionModel>( TreeViewBase );
            AliasTree.ItemsSource = TVData ;
            AliasTree.UpdateLayout();
            return;
        }
        searchText = SearchBox.Text;

        if (TVData != null)
        {
            await Dispatcher.InvokeAsync(
            () =>
            {
                foreach (ConnectionModel cm in TVData.ToList<ConnectionModel>())
                {
                    foreach (SchemaModel sm in cm.schemas.ToList<SchemaModel>())
                    {
                        foreach (SchemaCollection sc in sm.schema_collections.ToList<SchemaCollection>())
                        {
                            try
                            {
                                ObservableCollection<TableModel> octm = (ObservableCollection<TableModel>)sc.collection;
                                for (int i = 0; i < octm.Count; i++)
                                {
                                    if (!(sc.collection as ObservableCollection<TableModel>)[i].TABLE_NAME.Contains(searchText))
                                    {
                                        (sc.collection as ObservableCollection<TableModel>).RemoveAt(i);
                                        i = i - 1;
                                    }
                                    Dispatcher.InvokeAsync( () => OnPropertyChanged("tables") ) ;
                                }
                                Dispatcher.InvokeAsync(() => OnPropertyChanged("collection") );
                            }
                            catch (Exception exc) { }
                        }
                        Dispatcher.InvokeAsync(() => OnPropertyChanged("schemas") );
                    }
                    Dispatcher.InvokeAsync(() => OnPropertyChanged("TVData"));
                }
                Dispatcher.InvokeAsync(() => OnPropertyChanged("TVData"));
            });
            await Dispatcher.InvokeAsync(() => ExpandAll(AliasTree));
        }
    }

    private void ExpandAll( ItemsControl root )
    {
        if ( root != null )
        {
            foreach (var subItem in root.Items)
            {
                if (subItem != null)
                {
                    ExpandAll( (TreeViewItem)root.ItemContainerGenerator.ContainerFromItem(subItem) );
                    try
                    {
                        if (((TreeViewItem)root.ItemContainerGenerator.ContainerFromItem(subItem) as TreeViewItem) != null )
                            ((TreeViewItem)root.ItemContainerGenerator.ContainerFromItem(subItem) as TreeViewItem).IsExpanded = true;
                    }
                    catch (Exception exc) { };
                }
            }
            AliasTree.UpdateLayout();
        }
    }

感谢您的任何建议。

TVData = TreeViewBase;