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

Without custom helpers I recommend either ?.Any() ?? false or ?.Any() == true which are relatively concise and only need to specify the sequence once.

---

When I want to treat a missing collection like an empty one, I use the following extension method:

public static IEnumerable<T> OrEmpty<T>(this IEnumerable<T> sequence)
{
    return sequence ?? Enumerable.Empty<T>();
}

This function can be combined with all LINQ methods and foreach, not just .Any(), which is why I prefer it over the more specialized helper functions people are proposing here.

Answer 2

The way I do it, taking advantage of some modern C# features:

Option 1)

public static class Utils {
    public static bool IsNullOrEmpty<T>(this IEnumerable<T> list) {
        return !(list?.Any() ?? false);
    }
}

Option 2)

public static class Utils {
    public static bool IsNullOrEmpty<T>(this IEnumerable<T> list) {
        return !(list?.Any()).GetValueOrDefault();
    }
}

And by the way, never use Count == 0 or Count() == 0 just to check if a collection is empty. Always use Linq's .Any()

Answer 3

I used simple if to check for it

check out my solution

foreach (Pet pet in v.Pets)
{
    if (pet == null)
    {
        Console.WriteLine(" No pet");// enumerator is empty
        break;
    }
    Console.WriteLine("  {0}", pet.Name);
}

Answer 4

I had the same problem and I solve it like :

    public bool HasMember(IEnumerable<TEntity> Dataset)
    {
        return Dataset != null && Dataset.Any(c=>c!=null);
    }

"c=>c!=null" will ignore all the null entities.