Check if objects type inherits an abstract type

Question

Say I have an object, someDrink. It could be of type CocaCola or Pepsi which both inherit the abstract Cola (which inherits Drink) or any kind of drink for that matter. I have a method that returns a string of the most preferred beverage.

public string PreferredDrink(Drink someDrink)
{
    var orderOfPreference = new List<Type> {
        typeof (Cola),
        typeof (PurpleDrank),
        typeof (LemonLimeBitters)
        ...
    }

    foreach (drinkType in orderOfPreference) {
        if (someDrink.GetType() == drinkType) {
            return someDrink.ToString()
        }
    }

    throw new Exception("Water will be fine thank you");
}

The code above will not work, because the type of someCola can never be equal to an abstract type. Ideally I would like to do something like:

if (someCola is drinkType) ...

But the is keyword only allows a class name after it.

Is there another way to check if someDrink inherits a given type?

Refactoring isn't totally out of the question if you can suggest a better way to do this.

Answer 1

Sure - you can use Type.IsAssignableFrom:

if (drinkType.IsAssignableFrom(someDrink.GetType()))

Note that it's important that you don't get the target of the call and the argument the wrong way round. I have to consult the docs every time I use it, which is fortunately rarely :)