public void DeleteCourseFolder(Guid courseFolderId)
        {
            CourseFolderDE courseFolder = _context.tbl_db_course_folder.Where(x => x.CourseFolderId == courseFolderId).FirstOrDefault();

            if (courseFolder == null)
            {
                throw new AppException("CourseFolderId does not exist");
            }

            _context.tbl_db_course_folder.Remove(courseFolder);
            _context.SaveChanges();
        }
        public CourseFolderDE CreateCourseFolder(CourseFolderDto courseFolderDto)
        {
            if (!_courseRepository.CourseExists(courseFolderDto.CourseId))
            {
                throw new AppException("CourseId " + courseFolderDto.CourseId + "does not exist");
            }

            CourseFolderDE courseFolder = _mapper.Map <CourseFolderDE>(courseFolderDto);

            courseFolder.CourseFolderId = new Guid();

            _context.tbl_db_course_folder.Add(courseFolder);
            _context.SaveChanges();

            return(courseFolder);
        }