public CourseDisplayDto AdminGetCourseById(int courseId) { var course = courseRepository.AdminGetCourseById(courseId); if (course == null) { return(null); } var displayCourse = new CourseDisplayDto { CourseId = course.CourseId, Name = course.Name, Description = course.Description, CreatedOn = course.CreatedOn, Lecturer = new LecturerDisplayDto { Name = course.Publisher.NickName } }; return(displayCourse); }