public async Task <IActionResult> Delete()
        {
            if (!string.IsNullOrEmpty(RouteData.Values["id"].ToString()))
            {
                var id     = int.Parse(RouteData.Values["id"].ToString());
                var lesson = new DAL.Lesson
                {
                    LESSONID = id
                };
                await _lesson.DeleteLesson(lesson);

                await AddLog(id + " numaralı ders silindi.");
            }
            return(RedirectToAction("Index"));
        }