how to get email address from intranet application

That is true, but just like an application needs a connection string login to a database, it needs one for AD as well.

See below

<pre>public Dictionary<String, String> GetContacts()
{
Dictionary<String, String> contactList = new Dictionary<String, String>();

DirectoryEntry entry = new DirectoryEntry("LDAP://yourdomain/OU=UserGroupName,OU=Users,DC=domain,DC=local");
entry.Username = "adminUserName"; //<-- This is your full admin rights user for connection to AD
entry.Password = "adminPassword";

DirectorySearcher searcher = new DirectorySearcher(entry);

searcher.Filter = "(&(objectClass=user))";
searcher.PropertiesToLoad.Add("sAMAccountName");

SearchResultCollection result = searcher.FindAll();

String loginName = String.Empty,
firstName = String.Empty,
surname = String.Empty,
mail = String.Empty;

try
{
foreach (SearchResult userObject in result)
{
if (userObject != null)
{
PropertyCollection props = userObject.GetDirectoryEntry().Properties;

if (!Convert.ToBoolean((int)props["userAccountControl"].Value & 0x0002))
{
// Get the user's login name and firstname.
// Only get the surname and mail address if surname != null

if (props["sAMAccountName"].Value != null)
{
loginName = props["sAMAccountName"].Value.ToString();
}

if (props["givenname"].Value != null)
{
firstName = props["givenname"].Value.ToString();
}



if (props["sn"].Value != null)
{
surname = " " + props["sn"].Value.ToString();
}

// This line gets the email value
if (props["mail"].Value != null)
{
mail = props["mail"].Value.ToString();
}

contactList.Add(firstName + surname, mail);

}
}
}

if (contactList.Count > 0)
{
var sortedList = (from item in contactList orderby item.Value ascending select item);
contactList = sortedList.ToDictionary(sourceKeyValuePair => sourceKeyValuePair.Key, sourceKeyValuePair => sourceKeyValuePair.Value);
}
}
catch { }
return contactList;
}</pre>