IterateFiles - Return a IEnumerable of strings.

OsHelper.cs

using System.Collections.Generic;
using System.IO;

namespace SyncFTP
{
    public static class OsHelper
    {/// <summary>
     /// 
     /// </summary>
     /// <param name="path"></param>
     /// <param name="pattern"></param>
     /// <returns></returns>
        public static IEnumerable<string> IterateFiles(string path, string pattern)
        {
            var entryQueue = new Queue<string>();
            entryQueue.Enqueue(path);

            while (entryQueue.Count > 0)
            {
                var subdirs = Directory.GetDirectories(entryQueue.Peek());
                var files = Directory.GetFiles(entryQueue.Peek(), pattern, SearchOption.TopDirectoryOnly);

                foreach (var file in files)
                    yield return file;

                entryQueue.Dequeue();

                foreach (var subdir in subdirs)
                    entryQueue.Enqueue(subdir);
            }
        }
    }
}