public void StopObservingCar(Car car) { car.RemoveObserver(this, new NSString("makeModel")); car.RemoveObserver(this, new NSString("datePurchased")); car.RemoveObserver(this, new NSString("condition")); car.RemoveObserver(this, new NSString("onSpecial")); car.RemoveObserver(this, new NSString("price")); car.RemoveObserver(this, new NSString("photo")); }