public ActionResult RemoveCoverImage(CoverImageInputModel input)
        {
            CourseBll bll = new CourseBll();

            bll.RemoveCoverImage(input.CourseId);
            return(Json(new SuccessJsonResponse(), JsonRequestBehavior.AllowGet));
        }
        public ActionResult AddCoverImage(CoverImageInputModel input)
        {
            CourseBll bll    = new CourseBll();
            string    imgUrl = UeditorContentFactory.FetchUrl(
                input.CoverImage, UeditorType.Image);

            bll.AddCoverImage(input.CourseId, imgUrl);
            return(Json(new SuccessJsonResponse()));
        }