enum OrderService { AMBULANCE,HOME_HEALTH_CARE,Comprehensive_Medical_Checkup } extension SelectedOrderService on OrderService { int getIdOrderService() { switch (this) { case OrderService.AMBULANCE: return 4; break; case OrderService.Comprehensive_Medical_Checkup: return 3; break; case OrderService.HOME_HEALTH_CARE: return 2; break; } return 4; } OrderService getOrderServiceById(int id) { switch (id) { case 4: return OrderService.AMBULANCE; break; case 2: return OrderService.HOME_HEALTH_CARE; break; case 3: return OrderService.Comprehensive_Medical_Checkup; break; } return OrderService.AMBULANCE; } }