Combine Multiple Predicates

How about:

public static Predicate<T> Or<T>(params Predicate<T>[] predicates)
{
    return delegate (T item)
    {
        foreach (Predicate<T> predicate in predicates)
        {
            if (predicate(item))
            {
                return true;
            }
        }
        return false;
    };
}

And for completeness:

public static Predicate<T> And<T>(params Predicate<T>[] predicates)
{
    return delegate (T item)
    {
        foreach (Predicate<T> predicate in predicates)
        {
            if (!predicate(item))
            {
                return false;
            }
        }
        return true;
    };
}

Then call it with:

List<string> filteredNames = names.FindAll(Helpers.Or(StartsWithE, StartsWithI));

Another alternative would be to use multicast delegates and then split them using GetInvocationList(), then do the same thing. Then you could do:

List<string> filteredNames = names.FindAll(Helpers.Or(StartsWithE+StartsWithI));

I’m not a huge fan of the latter approach though – it feels like a bit of an abuse of multicasting.