Asp.net给站点某目录增加Aspnet用户

using  System;
using  System.Data;
using  System.Configuration;
using  System.Collections;
using  System.Web;
using  System.Web.Security;
using  System.Web.UI;
using  System.Web.UI.WebControls;
using  System.Web.UI.WebControls.WebParts;
using  System.Web.UI.HtmlControls;

using  System.IO;
using  System.Net;
using  System.Security.AccessControl;
using  System.Security.Principal;

public  partial  class  ACLChange : System.Web.UI.Page
{
     // 文件夹路径
     private   string  strDir  =   " images " ;

     protected   void  Page_Load( object  sender, EventArgs e)
    {
         if  ( ! IsPostBack)
        {
            AddDirectorySecurity();
        }
    }

     ///   <summary>
     ///  给文件夹添加ASPNET用户
     ///   </summary>
     private   void  AddDirectorySecurity()
    {
        DirectoryInfo dirinfo  =   new  DirectoryInfo(Server.MapPath(strDir));

         if  ((dirinfo.Attributes  &  FileAttributes.ReadOnly)  !=   0 )
        {
            dirinfo.Attributes  =  FileAttributes.Normal;
        }

         // 取得访问控制列表
        DirectorySecurity dirsecurity  =  dirinfo.GetAccessControl();

         string  strDomain  =  Dns.GetHostName();

        dirsecurity.AddAccessRule( new  FileSystemAccessRule(strDomain  +   " \\ASPNET " , FileSystemRights.FullControl, AccessControlType.Allow));

        dirinfo.SetAccessControl(dirsecurity);
    }
}