FileStream,FileInfo,DirectoryInfo，主要就是这几个东西了。下面是个示例代码

ArrayList GetAll(DirectoryInfo dir)//搜索文件夹中的文件
        {
            ArrayList FileList = new ArrayList();

            FileInfo[] allFile = dir.GetFiles();
            foreach (FileInfo fi in allFile)
            {
                FileList.Add(fi.Name);
            }

            DirectoryInfo[] allDir= dir.GetDirectories();
            foreach (DirectoryInfo d in allDir)
            {
                GetAll(d);
            }
            return FileList;
        }
DirectoryInfo d = new DirectoryInfo(@"F:\");
  ArrayList Flst= GetAll(d);