using System.Collections.Generic;
using System.Reflection;
using Microsoft.Office.Interop.Outlook;

namespace GAL
{
   //add a reference to Microsoft Outlook 12.0 Object Library
   class COutLook
   {
       public struct User
       {
           public string Name;
           public string Email;
       }

       public static List<User> ExchangeServerEmailAddresses(string userName)
       {
           List<User> res = new List<User>();
           //Create Outlook application
           Application outlookApp = new Application();
           //Get Mapi NameSpace and Logon
           NameSpace ns = outlookApp.GetNamespace("MAPI");
           ns.Logon(userName, Missing.Value, false, true);

           //Get Global Address List
           AddressLists addressLists = ns.AddressLists;
           AddressList globalAddressList = addressLists["Global Address List"];
           AddressEntries entries = globalAddressList.AddressEntries;
           foreach (AddressEntry entry in entries)
           {
               ExchangeUser user = entry.GetExchangeUser();
               if (user != null && user.PrimarySmtpAddress != null && entry.Name != null)
                   res.Add(new User
                           {
                               Name = entry.Name,
                               Email = user.PrimarySmtpAddress
                           });
           }

           ns.Logoff();

           // Clean up.
           outlookApp = null;
           ns = null;
           addressLists = null;
           globalAddressList = null;
           entries = null;

           return res;
       }
   }
}

List<COutLook.User> data = COutLook.ExchangeServerEmailAddresses("nasiri");
foreach (var list in data)
{
  //....
}