I assume that "city view" is part of the room category here? I would expect the hotel to upgrade you, although you might have to negotiate if the upgraded room isn't city view but instead to something like "super deluxe executive parking lot view." They can't just give you the "standard no view" when you booked "standard city view" without compensation (even if the two room types carry the same rate), but I don't know the official rules, if there are some. This is similar to but different from the issue of bedding type being guaranteed.