无法访问LDAP中的sn, givenName

我是c#的新手，我使用LDAP来1)验证用户的登录凭据，2)为我的应用程序获取有关用户的其他信息。我们的LDAP服务器不允许我请求匿名分发的一些数据，所以我必须等到我绑定了用户的完整凭据才能提取数据。然而，即使这样，我也无法获得简单的字段，如sn和givenName。使用JXplorer，我可以看到在匿名连接期间隐藏这些值的位置，但是使用完整的用户/SSL/密码组合，我可以看到JXplorer中的所有内容。我只是不能通过我的代码做同样的事情。

如果我在第一个FindOne()之后循环遍历属性，会发现9个属性(其中没有一个是我正在寻找的)。如果我在第二个 FindOne()之后循环遍历属性，则只有4个属性可用。这两个结果似乎都没有受到PropertiesToAdd.Add("…")的影响。

如有任何建议，不胜感激。

public string[] Authenticate(string user,  string password)
    {
         string[] results = new string [2];
        //Concatenate serverpath + username + container
        //I.e.  "LDAP://ldap.disney.com:636/CN=donaldDuck,ou=people,dc=la,dc=disney,dc=com"
        DirectoryEntry de = new DirectoryEntry(_ldapserver + "cn=" + user + "," + _topContainer);
        //User's password for initial verification
        de.Password = password;
        //initate anonymous bind
        de.AuthenticationType = System.DirectoryServices.AuthenticationTypes.SecureSocketsLayer;
        DirectorySearcher searcher = new DirectorySearcher(de);
        searcher.SearchScope = System.DirectoryServices.SearchScope.Base;
        //Search for first record
        SearchResult result = searcher.FindOne();
        //Check results
        if (result == null) throw new Exception(ERR_NOT_FOUND);
        de = result.GetDirectoryEntry();
        //Return search results
        //results[0] = (string)de.Properties["mail"].Value;
        // results[1] = (string)de.Properties["givenName"].Value + " " + (string)de.Properties["sn"].Value;
        // Distingushed Name of the found account
        string DN = de.Path.Substring(de.Path.ToUpper().IndexOf("CN="));
        // Close search connection
        de.Close();

        // now bind and verify the user's password,
        de = new DirectoryEntry(_ldapserver + _topContainer);
        de.Username = DN;
        de.Password = password;
        de.AuthenticationType = System.DirectoryServices.AuthenticationTypes.SecureSocketsLayer;
        //Obtain additional information
         searcher = new DirectorySearcher(de);
         searcher.PropertiesToLoad.Add("sn");
         searcher.PropertiesToLoad.Add("givenName");
         SearchResult r = searcher.FindOne();
         de = r.GetDirectoryEntry();
        foreach (string property in de.Properties.PropertyNames)
         {
           Console.WriteLine("'t{0} : {1} ", property, de.Properties[property][0]);
         }
        //End obtain additional information
        //Validate password
        Object obj = de.NativeObject;
        de.Close();
        //if we made it here, we successfully authenticated
        return results;
    }

// set up domain context
using (PrincipalContext ctx = new PrincipalContext(ContextType.Domain))
{
   // validate given user credentials
   bool isValid = ctx.ValidateCredentials(user, password);
   // find a user
   UserPrincipal user = UserPrincipal.FindByIdentity(ctx, "SomeUserName");
   if(user != null)
   {
      string surname = user.Surname;
      string givenName = user.GivenName;
   }
}