public ActionResult AddTopicMethod()
        {
            Topic topic = new Topic();

            topic.TopicID  = Convert.ToInt32(Request["TopicId"]);
            topic.Title    = Request["TopicTitle"];
            topic.AnswerA  = Request["AnswerA"];
            topic.AnswerB  = Request["AnswerB"];
            topic.AnswerC  = Request["AnswerC"];
            topic.AnswerD  = Request["AnswerD"];
            topic.Answer   = Request["Answer"];
            topic.CourseID = Convert.ToInt32(Request["CourseID"]);
            ITopicBLL topicBLL = new TopicManager();

            if (topicBLL.AddEntity(topic))
            {
                return(Content("<script>alert('添加成功!');window.location.href='/Home/TopicManager';</script>"));//刷新页面
            }
            else
            {
                return(Content("<script>alert('添加失败!');history.go(-1);</script>"));//不刷新退回页面
            }
        }