1: public static string GetUsersEmail(string User, string UserName, string Password)

   2: {

   3:    string EmailAddress = "";

   4:    DirectoryEntry Entry = new DirectoryEntry("LDAP://ADserver",   //Make sure to point this at your AD server

   5:                                                UserName,

   6:                                                Password,

   7:                                                AuthenticationTypes.Secure);

   8:    DirectorySearcher Searcher = new DirectorySearcher(Entry);

   9:    Searcher.PropertiesToLoad.Add("mail");

  10:    string Filter = String.Format("(&(objectcategory=user)(cn=" + User + "))"); 

  11:  

  12:    Searcher.Filter = Filter;

  13:    Searcher.Sort.Direction = SortDirection.Ascending;

  14:    Searcher.Sort.PropertyName = "cn"; 

  15:  

  16:    SearchResultCollection Results; 

  17:  

  18:    Results = Searcher.FindAll(); 

  19:  

  20:    foreach (SearchResult Result in Results)

  21:    {

  22:       ResultPropertyCollection Properties = Result.Properties;

  23:       foreach (string Key in Properties.PropertyNames)

  24:       {

  25:          if (Key == "mail")

  26:          {

  27:             foreach (object Values in Properties[Key])

  28:             {

  29:                EmailAddress = Values.ToString();

  30:                break;

  31:             }

  32:          }

  33:       }

  34:    }

  35:    return EmailAddress;

  36: }