public bool IsADUsernameExistsAndNotDisabled(string userName)
    {
        bool _return = false;
        if (userName.Length > 0)
        {
            string ldapConnection = ConfigurationManager.AppSettings["ADConnection"].ToString();
            string eCrewUserName = ConfigurationManager.AppSettings["ADUserName"].ToString();
            string eCrewUserPassword = ConfigurationManager.AppSettings["ADPassword"].ToString();
 
            DirectoryEntry searchRoot = new DirectoryEntry(ldapConnection, eCrewUserName, eCrewUserPassword);