using System; using System.DirectoryServices.AccountManagement; namespace new_ad_exmaple { class Program { static void Main(string[] args) { try { PrincipalContext AD = new PrincipalContext(ContextType.Domain, "leeds-art.ac.uk"); UserPrincipal u = new UserPrincipal(AD); PrincipalSearcher search = new PrincipalSearcher(u); foreach(UserPrincipal result in search.FindAll()) if (result.VoiceTelephoneNumber != null) Console.WriteLine("{0,30} {1} ", result.DisplayName, result.VoiceTelephoneNumber); search.Dispose(); } catch (Exception e) { Console.WriteLine("Error: " + e.Message); } } } }