C# 如何获得“目标”；ntSecurityDescriptor“；active directory用户的名称

我在一个网站上工作。我必须找到用户的值不能更改用户的密码属性。我得到这个链接 http://msdn.microsoft.com/en-us/library/aa746448（v=vs.85）.aspx[^] 根据它，我必须找到该用户的“ntSecurityDescriptor”值。他们使用DirectoryEntry类来查找，但在我的例子中，我使用的是LdapConnection类。 若我使用entry类，我将无法与服务器建立连接，所以我将其更改为LdapConnection类。现在我不知道如何找到价值。

我找到了我的解决方案

 SearchResponse response = (SearchResponse)connection.SendRequest(request);
            DirectoryAttribute attribute = response.Entries[0].Attributes["ntSecurityDescriptor"];

            if (attribute != null)
            {
                const string PASSWORD_GUID = "{ab721a53-1e2f-11d0-9819-00aa0040529b}";
                const int ADS_ACETYPE_ACCESS_DENIED_OBJECT = 6;
                bool fEveryone = false;
                bool fSelf = false;

                ActiveDs.ADsSecurityUtility secUtility = new ActiveDs.ADsSecurityUtility();
                ActiveDs.IADsSecurityDescriptor sd = (IADsSecurityDescriptor)secUtility.ConvertSecurityDescriptor((byte[])attribute[0], (int)ADS_SD_FORMAT_ENUM.ADS_SD_FORMAT_RAW, (int)ADS_SD_FORMAT_ENUM.ADS_SD_FORMAT_IID);
                ActiveDs.IADsAccessControlList acl = (ActiveDs.IADsAccessControlList)sd.DiscretionaryAcl;

                foreach (ActiveDs.IADsAccessControlEntry ace in acl)
                {
                    if ((ace.ObjectType != null) && (ace.ObjectType.ToUpper() == PASSWORD_GUID.ToUpper()))
                    {
                        if ((ace.Trustee == "Everyone") && (ace.AceType == ADS_ACETYPE_ACCESS_DENIED_OBJECT))
                        {
                            fEveryone = true;
                        }
                        if ((ace.Trustee == @"NT AUTHORITY\SELF") && (ace.AceType == ADS_ACETYPE_ACCESS_DENIED_OBJECT))
                        {
                            fSelf = true;
                        }

                        break;
                    }
                }

                if (fEveryone || fSelf)
                {
                    return Global.RequestContants.CANT_CHANGE_PASSWORD;
                }
                else
                {
                    return string.Empty;
                }
            }