private bool AddTopic(String path)
        {
            bool r = app.AddAnTopicFolder(path);

            if (!r)
            {
                MsgBoxYesNo msg = new MsgBoxYesNo("Cann't add this folder as topic. Retry ?");
                if ((bool)msg.ShowDialog())
                {
                    return(AddTopic(path));
                }
                else
                {
                    return(false);
                }
            }
            else
            {
                active_topic++;
                questionItem[active_topic].Title.Content          = topics[active_topic - 1].Name;
                questionItem[active_topic].MaxScore.Content       = "High score : " + topics[active_topic - 1].HightScore + '/' + topics[active_topic - 1].QuestionNumber;
                questionItem[active_topic].QuestionNumber.Content = "Question Number : " + topics[active_topic - 1].QuestionNumber;

                return(true);
            }
        }
        private void ActionText_MouseUp(object sender, MouseButtonEventArgs e)
        {
            switch (state)
            {
            case State.COLLECTION_SHOWN: break;

            case State.TESTING:
                MsgBoxYesNo msgbox = new MsgBoxYesNo("Quit the test will lost everything.\n Comfirm ?");
                if ((bool)msgbox.ShowDialog())
                {
                    //do yes stuff
                    state = State.COLLECTION_SHOWN;
                    Containner.Children.Remove(TestScreen);
                    TestScreen            = null;
                    grid.Visibility       = Visibility.Visible;
                    actionText.Foreground = new SolidColorBrush(Color.FromRgb(161, 161, 161));
                    StackRoot.Background  = new SolidColorBrush(Color.FromRgb(255, 255, 255));
                    actionText.Content    = "Chọn bộ câu hỏi (" + topics.Count + ") ";
                }
                else
                {
                    // no
                }

                break;

            case State.RESULT_SCREEN: break;
            }
        }