Re: Casting/converting generic list types

Mont Rothstein wrote:
> If I have List<A> where all of the elements are of type B.  How do I get
> List<B> from List<A>?  Do I have to iterate over List<A> and add each
> element to List<B>?

Yes, I'm afraid so.

> I've tried using "as List<B>" and "(List<B>)" both to no avail.
> List<T>.AddRange() must be of the same type T.
>
> ConvertAll() is an O(n) operation, and does a conversion which I don't
> really need.

Do you definitely have a performance issue in that area of the code? How
big are the lists?

> I have this situation occur fairly frequently because A is an  abstract
> superclass of a number of different classes and it has a method to return a
> List of objects of a subclass, but that list is always homogeneous.

Can you not just use a List<A> everywhere instead?

Jon

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