无法从 UI 主题更新富文本框..?

Can't update rich textbox from UI Thread..?

我有这个方法 return 是一个 FlowDocument。

    private static FlowDocument SortFriendsList()
    {
        FlowDocument DocumentToReturn = new FlowDocument();
        Paragraph CurrentParagraph = new Paragraph();
        #region Online status ellipse
        System.Windows.Shapes.Ellipse OnlineStatus = new System.Windows.Shapes.Ellipse();
        OnlineStatus.Height = 30;
        OnlineStatus.Width = 30;
        OnlineStatus.Stroke = System.Windows.Media.Brushes.Black;
        OnlineStatus.StrokeThickness = 1.5;
        OnlineStatus.Fill = System.Windows.Media.Brushes.Green;
        #endregion
        #region Offline status ellipse
        System.Windows.Shapes.Ellipse OfflineStatus = new System.Windows.Shapes.Ellipse();
        OfflineStatus.Height = 30;
        OfflineStatus.Width = 30;
        OfflineStatus.Stroke = System.Windows.Media.Brushes.Black;
        OfflineStatus.StrokeThickness = 1.5;
        OfflineStatus.Fill = System.Windows.Media.Brushes.Red;
        #endregion

        if (CurrentFriendsList.Count == 0)
        {
            Label TextToShow = new Label();
            TextToShow.FontSize = 16;
            TextToShow.Foreground = System.Windows.Media.Brushes.Black;
            TextToShow.Content = "Uh oh... It looks like you have no friends for now :(";
            CurrentParagraph.Inlines.Add(TextToShow);
            CurrentParagraph.Inlines.Add(Environment.NewLine);
            DocumentToReturn.Blocks.Add(StatusParagraph);
            return DocumentToReturn;
        }
        else
        {
            foreach (string Friend in CurrentFriendsList)
            {

                if (CurrentOnlineUsers.Contains(Friend))
                {

                    CurrentParagraph.Inlines.Add(OnlineStatus);
                }
                else
                {

                    CurrentParagraph.Inlines.Add(OfflineStatus);
                }
                #region Text to add after status ellipse
                Label TextToShow = new Label();
                TextToShow.FontSize = 16;
                TextToShow.Foreground = System.Windows.Media.Brushes.Black;
                TextToShow.Content = Friend;
                #endregion
                CurrentParagraph.Inlines.Add(TextToShow);
                CurrentParagraph.Inlines.Add(Environment.NewLine);
                DocumentToReturn.Blocks.Add(StatusParagraph);
            }
            return DocumentToReturn;
        }
    }

我正在调用这样的方法来更新富文本框的文档:

                App.Current.Dispatcher.Invoke(() => 
                {
                    try
                    {
                        WindowController.MainPage.FriendsListTextBox.Document = SortFriendsList();
                    }
                    catch (Exception Exc)
                    {
                        Console.WriteLine(Exc.ToString());
                    }
                });

不过。出于某种原因,我得到

Exception thrown: 'System.InvalidOperationException' in WindowsBase.dll System.InvalidOperationException: The calling thread cannot access this object because a different thread owns it.

富文本框位于选项卡项内,我尝试使用它的调度程序,但没有成功。我已经尝试过页面、window 和富文本框的调度程序,但都没有成功。有没有办法找到它的调度员?也许是 return App.Current 中所有调度程序的数组或列表同时尝试执行 dispatcher.checkaccess 的方法? 提前致谢:)

我最终将我的方法移动到 App.xaml.cs 然后调用它:

            App.Current.Dispatcher.Invoke(() => 
            {
                try
                {
                    WindowController.MainPage.FriendsListTextBox.Document = SortFriendsList();
                }
                catch (Exception Exc)
                {
                    Console.WriteLine(Exc.ToString());
                }
            });