public async Task <dynamic> OnPostAsync([FromForm] Course course, [FromForm] List <string> teachers, [FromForm] string token)
        {
            try
            {
                var t = await tokenService.GetTokenAsync(token);

                if (t == null)
                {
                    throw new Exception("请先登录");
                }
                if (t.Role != UserRole.Admin)
                {
                    throw new Exception("权限不足");
                }
                var id = await courseService.AddCourseAysnc(course);

                foreach (var teacher in teachers)
                {
                    await courseService.AddTeacherToCouseAsync(id, teacher);
                }
                return(new { Res = true, CourseID = id });
            }
            catch (Exception e)
            {
                return(new { Res = false, Error = e.Message });
            }
        }