How to create an arraylist of all email addresses in an Active Directory OU in an asp.net c# web forms application?

Question

I have read several posts, but I haven't been able to get anything to work for me. I would like to create an arraylist of all display names within the "Standard Users" OU. I will then use that arraylist to populate a dropdown list. I found the following in another thread, but it provides groups and not users within the specified OU:

public ArrayList Groups()
{
    ArrayList groups = new ArrayList();
    foreach (System.Security.Principal.IdentityReference group in
        System.Web.HttpContext.Current.Request.LogonUserIdentity.Groups)
    {
        groups.Add(group.Translate(typeof
            (System.Security.Principal.NTAccount)).ToString());
    }

    return groups;
}

Can this be modified to provide the list of users in the Standard Users OU? Or should I use a different approach?

I also found this, but I get an error (red lines under 'std_users') stating 'not all code paths return a value'.

public ArrayList std_users()
{
    // List of strings for your names
    List<string> allUsers = new List<string>();

    // create your domain context and define the OU container to search in
    PrincipalContext ctx = new PrincipalContext(ContextType.Domain, "myco.org", "OU=Standard Users, dc=myco, dc=org");

    // define a "query-by-example" principal - here, we search for a UserPrincipal (user)
    UserPrincipal qbeUser = new UserPrincipal(ctx);

    // create your principal searcher passing in the QBE principal    
    PrincipalSearcher srch = new PrincipalSearcher(qbeUser);

    // find all matches
    foreach (var found in srch.FindAll())
    {
        // do whatever here - "found" is of type "Principal" - it could be user, group, computer.....          
        allUsers.Add(found.DisplayName);
    }
}

Any help would be greatly appreciated.

I am using c#, Visual Studio 2013 and the framework is 4.5.1.

Answer 1

First off: STOP USING ArrayList - that type is dead since .NET 2.0 and should not be used - use List<string> (or more generally: List<T> ) instead - much better for performance and usability!

You can use a PrincipalSearcher and a "query-by-example" principal to do your searching:

public List<string> GetAllEmailsFromUsersContainer()
{
    List<string> users = new List<string>();

    // create your domain context and bind to the standard CN=Users
    // container to get all "standard" users
    using (PrincipalContext ctx = new PrincipalContext(ContextType.Domain, null, "CN=Users,dc=YourCompany,dc=com"))
    {
        // define a "query-by-example" principal - here, we search for a UserPrincipal 
        // which is not locked out, and has an e-mail address   
        UserPrincipal qbeUser = new UserPrincipal(ctx);
        qbeUser.IsAccountLockedOut = false;
        qbeUser.EmailAddress = "*";

        // create your principal searcher passing in the QBE principal    
        PrincipalSearcher srch = new PrincipalSearcher(qbeUser);

        // find all matches
        foreach(var found in srch.FindAll())
        {
            users.Add(found.EmailAddress);
        }
    }

    return users;
}

Answer 2

Add return allUsers; to std_users() and let us know if that works for you.