PeoplePickerRemediation.Console.PeoplePickerRemediation.GetUPN C# (CSharp) Method

        private static string GetUPN(string accountType, string samaccountname)
        {
            string ldapQuery = ConfigurationManager.AppSettings["LocalAdLdapQuery"].ToString();

            // Bind to the users container.
            DirectoryEntry entry = new DirectoryEntry(ldapQuery);
            // Create a DirectorySearcher object.
            DirectorySearcher mySearcher = new DirectorySearcher(entry);
            // Create a SearchResultCollection object to hold a collection of SearchResults
            // returned by the FindAll method.
            mySearcher.PageSize = 500;  // ADD THIS LINE HERE !
            string strFilter = string.Empty;
            if (accountType.ToLower().Equals("user"))
                strFilter = string.Format("(&(objectCategory=User)(SAMAccountName={0}))", samaccountname);
            else if (accountType.ToLower().Contains("group"))
                strFilter = string.Format("(&(objectCategory=Group)(sid={0}))", samaccountname);
            var propertiesToLoad = new[] { "SAMAccountName", "userprincipalname", "sid" };
            mySearcher.PropertiesToLoad.AddRange(propertiesToLoad);
            mySearcher.Filter = strFilter;
            mySearcher.CacheResults = false;
            SearchResultCollection result = mySearcher.FindAll();

            if (result.Count > 0)
            {
                return GetProperty(result[0], "userprincipalname");
            }

            return string.Empty;
        }