首先需导入命名空间：using System.IO;           

string path = @"D:\";

DirectoryInfo dir = new DirectoryInfo(path);
            foreach(FileSystemInfo fsi in dir.GetFileSystemInfos())
            {
                if (fsi is FileInfo)
                {
                    FileInfo fi = (FileInfo)fsi;
                    //获得文件
                }
                else
                {
                    DirectoryInfo di = (DirectoryInfo)fsi;
                    //获得文件夹
                }
            }

这样可以获取一个目录里的所有内容：包括文件和文件夹