How to check if IEnumerable is null or empty?

Question

I love string.IsNullOrEmpty method. I\'d love to have something that would allow the same functionality for IEnumerable. Is there such? Maybe some collection he

Answer 1

Starting with C#6 you can use null propagation: myList?.Any() == true

If you still find this too cloggy or prefer a good ol' extension method, I would recommend Matt Greer and Marc Gravell's answers, yet with a bit of extended functionality for completeness.

Their answers provide the same basic functionality, but each from another perspective. Matt's answer uses the string.IsNullOrEmpty-mentality, whereas Marc's answer takes Linq's .Any() road to get the job done.

I am personally inclined to use the .Any() road, but would like to add the condition checking functionality from the method's other overload:

    public static bool AnyNotNull(this IEnumerable source, Func predicate = null)
    {
        if (source == null) return false;
        return predicate == null
            ? source.Any()
            : source.Any(predicate);
    }

So you can still do things like : myList.AnyNotNull(item=>item.AnswerToLife == 42); as you could with the regular .Any() but with the added null check

Note that with the C#6 way: myList?.Any() returns a bool? rather than a bool, which is the actual effect of propagating null