C# 删除文件夹下子文件夹

    var pathstr="E:/Time";
    try
    {    
       if (Directory.Exists(pathstr))
       {
          //var strname=DateTime.Now.ToShortDateString().Replace("/","-")+".txt";
          var dt=DateTime.Now;
          DirectoryInfo pathinfo=new DirectoryInfo(pathstr);
          foreach (DirectoryInfo paths in pathinfo.GetDirectories())
          {        
            //File.AppendAllText("E:\\Time\\新建文件夹 (2)"+"/"+strname,DateTime.Now+"\r\n");
            if (paths.CreationTime < Convert.ToDateTime(dt.AddDays(-(dt.Day)+1)))
            {
                paths.Delete();
            }
          }
       }
    }
    catch (Exception ex)
    {
        File.AppendAllText("E:\\Time\\Errlog.txt",ex+"\r\n");
    }