How to retrieve all users from Active Directory?

Question

I am new to asp.net, I have new tasks to retrieve all users from Active Directory. When I tried to retrieve all users from Active Directory I only got one user.

private void btngetuser_Click(object sender, EventArgs e)
{
        DirectorySearcher searcher = new DirectorySearcher();
        searcher.SearchScope = SearchScope.Subtree;
        searcher.Filter = string.Format(CultureInfo.InvariantCulture, "(sAMAccountName={0})", Environment.UserName);
        //SearchResult findUser = searcher.FindOne();

        foreach (SearchResult findUser in searcher.FindAll())
        {
            if (findUser != null)
            {
                DirectoryEntry user = findUser.GetDirectoryEntry();
                string userName = user.Properties["displayName"].Value.ToString();
                string Email = user.Properties["mail"].Value.ToString();
                string Mobile = user.Properties["Mobile"].Value.ToString();
                string Login = user.Properties["sAMAccountName"].Value.ToString();
                string[] rt = new string[] { Login, userName, Email, Mobile };
                dataGridView1.Rows.Add(rt);
            }
        }
    }

Answer 1

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

// create your domain context
using (PrincipalContext ctx = new PrincipalContext(ContextType.Domain))
{
   // define a "query-by-example" principal - here, we search for  UserPrincipal (users)
   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.....          
       UserPrincipal foundUser = found as UserPrincipal;

       if(foundUser != null)
       { 
            string userName = foundUser.DisplayName;
            string email = foundUser.Email;
            string login = foundUser.SamAccountName;
        }
   }
}

If you haven't already - absolutely read the MSDN article Managing Directory Security Principals in the .NET Framework 3.5 which shows nicely how to make the best use of the new features in System.DirectoryServices.AccountManagement . Or see the MSDN documentation on the System.DirectoryServices.AccountManagement namespace.

Answer 2

You're using a filter, right? Why are you expecting that this query filtered by login name would return all users in AD and not exactly what you asked it for?