C# Cannot convert from IEnumerable<Base> to IEnumerable

Question

I recently run into trouble when trying to AddRange(IEnumerable) to a List. Probably a classic issue, but I do not really get it yet.

I understand that methods expec

Answer 1

The cast solution of course might generated class cast exceptions. The person who posted the enumerable extension work around said it was awkward. I came up with a solution which is only half as awkward, don't know if I'll use it:

public static class UpTo
{
    public static IEnumerable From(IEnumerable source) where F:T
    {
        // this cast is guaranteed to work
        return source.Select(f => (T) f);
    }
}

Usage:

IEnumerable mammals = UpTo.From(kennel.Dogs)