public ActionResult Create(Student student)
 {
     try
     {
         student.Group = _dataManager.GroupManager.GetItem(Convert.ToInt32(Request.Form.Get("id_group")));
         _dataManager.StudentManager.Add(student);
         return RedirectToAction("List");
     }
     catch
     {
         return View();
     }
 }
 partial void DeleteStudent(Student instance);
 partial void UpdateStudent(Student instance);
 partial void InsertStudent(Student instance);
		private void detach_Students(Student entity)
		{
			this.SendPropertyChanging();
			entity.Group = null;
		}
		private void attach_Students(Student entity)
		{
			this.SendPropertyChanging();
			entity.Group = this;
		}