Traverse Nested Collections

NestedCollectionsExtentions_Traverse.cs

using System.Linq;
namespace System.Collections.Generic
{
    public static class NestedCollectionsExtentions
    {
        public static IEnumerable<T> Traverse<T>(this T node, Func<T, IEnumerable<T>> childrenFor)
        {
            yield return node;

            IEnumerable<T> enumerable = childrenFor(node);

            if (enumerable != null)
            {
                foreach (T current in enumerable.SelectMany((T n) => n.Traverse(childrenFor)))
                {

                    yield return current;
                }
            }

            yield break;
        }
    }
}