Re: Casting/converting generic list types

Mont Rothstein wrote:
> I may or may not have a performance issue, it is a potential problem.  I
> was
> primarily looking for a more elegant solution because looping over List<A>
> to create List<B> is just ugly.
>
> Even better than a standard way to convert/cast would be the ability to
> return a List<T> where T is either A or any subclass of A.  I'm not really
> sure why they didn't allow for this, perhaps it will get added in the
> future.
>
> Thank you both for your suggestions and for confirming what I feared.

Covariance and contravariance are supported for interface types at the
IL level, but C# doesn't support them.

As Andrew said, if you're happy with IList<T> instead of List<T>, you
could write a wrapper. You'll lose the compile-time type safety you get
with generics though. (If you wanted to return a List<B> as a List<A>
you wouldn't have type-safety issues, but you'd still need to write a
wrapper.)

Jon

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