Question

I find myself writing the following over and over:

if (myEnumerable != null) {
    foreach (var element in myEnumerable) {
        DoSomething(element);
    }
}

It’s tedious to check for NULL every time I want to enumerate, is there a better way? For instance, is there a way to override the enumerator to return “Enumerable.Empty” instead of NULL?

Answer 1

Well, ideally design your code so that it can’t be null. Alternatively, create an extension method:

 public static class EnumerableEx
 {
     public static IEnumerable<T> EmptyIfNull(this IEnumerable<T> source)
     {
         return source ?? Enumerable.Empty<T>();
     }
 }

Then:

foreach (var element in myEnumerable.EmptyIfNull())
    DoSomething(element);
}

This is much the same as Darin’s approach, but moves the null coalescing operator into an extension method.