public static void copyFiles(string path) {

     DirectoryInfo dir = new DirectoryInfo(path);

     if (!dir.Exists)

         return; //获得指定文件夹内的所有的子目录信息

     DirectoryInfo[] dirs = dir.GetDirectories(); //获得指定文件夹内所有的文件信息

     FileInfo[] files = dir.GetFiles();

     foreach (FileInfo file in files) {

         string fileName = file.Name;

         string desPath = "~/DownLoad-TargetFiles/" + fileName;
　　　　　　 file.CopyTo(desPath);

     }

      foreach (DirectoryInfo d in dirs) {

         string p = d.FullName;

         copyFiles(p);

     }

 }
                             

File.Move("C:\abc.txt","C:\abc.dat");