IEnumerable<string> GetFilesFromDir(string dir) =>
 Directory.EnumerateFiles(dir).Concat(
 Directory.EnumerateDirectories(dir)
          .SelectMany(subdir => GetFilesFromDir(subdir)));

IEnumerable<string> GetFilesFromDir(string dir) =>
 Directory.EnumerateFiles(dir).Concat(
 Directory.EnumerateDirectories(dir)
          .SelectMany(subdir => GetFilesFromDir(subdir)));

一个简单干净的解决方案

/// <summary>
/// Scans a folder and all of its subfolders recursively, and updates the List of files
/// </summary>
/// <param name="sFullPath">Full path of the folder</param>
/// <param name="files">The list, where the output is expected</param>
internal static void EnumerateFiles(string sFullPath, List<FileInfo> fileInfoList)
{
    try
    {
        DirectoryInfo di = new DirectoryInfo(sFullPath);
        FileInfo[] files = di.GetFiles();

        foreach (FileInfo file in files)
            fileInfoList.Add(file);

        //Scan recursively
        DirectoryInfo[] dirs = di.GetDirectories();
        if (dirs == null || dirs.Length < 1)
            return;
        foreach (DirectoryInfo dir in dirs)
            EnumerateFiles(dir.FullName, fileInfoList);

    }
    catch (Exception ex)
    {
        Logger.Write("Exception in Helper.EnumerateFiles", ex);
    }
}

这就是我们如何将文件作为其子目录的FileInfo，

var dir = new DirectoryInfo(rootPath);
FileInfo[] files = dir.GetFiles("*.*", SearchOption.AllDirectories);

一些改进版本，最大lvl下到目录和选项排除文件夹:

using System;
using System.IO;

class MainClass {
  public static void Main (string[] args) {

    var dir = @"C:\directory\to\print";
    PrintDirectoryTree(dir, 2, new string[] {"folder3"});
  }


  public static void PrintDirectoryTree(string directory, int lvl, string[] excludedFolders = null, string lvlSeperator = "")
  {
    excludedFolders = excludedFolders ?? new string[0];

    foreach (string f in Directory.GetFiles(directory))
    {
        Console.WriteLine(lvlSeperator+Path.GetFileName(f));
    } 

    foreach (string d in Directory.GetDirectories(directory))
    {
        Console.WriteLine(lvlSeperator + "-" + Path.GetFileName(d));

        if(lvl > 0 && Array.IndexOf(excludedFolders, Path.GetFileName(d)) < 0)
        {
          PrintDirectoryTree(d, lvl-1, excludedFolders, lvlSeperator+"  ");
        }
    }
  }
}

输入目录:

-folder1
  file1.txt
  -folder2
    file2.txt
    -folder5
      file6.txt
  -folder3
    file3.txt
  -folder4
    file4.txt
    file5.txt

函数的输出(由于lvl限制，folder5的内容被排除，folder3的内容被排除，因为它在excldedfolders数组中):

-folder1
  file1.txt
  -folder2
    file2.txt
    -folder5
  -folder3
  -folder4
    file4.txt
    file5.txt

static void Main(string[] args)
        {
            string[] array1 = Directory.GetFiles(@"D:\");
            string[] array2 = System.IO.Directory.GetDirectories(@"D:\");
            Console.WriteLine("--- Files: ---");
            foreach (string name in array1)
            {
                Console.WriteLine(name);
            }
            foreach (string name in array2)
            {
                Console.WriteLine(name);
            }
                  Console.ReadLine();
        }