public ActionResult Index(UserValidateModel model)
        {
            var findusers = model.SearchUser;
            var captchas = db.captchas.ToList();
            var captchasmodel = new UserCaptchaModel();
            captchasmodel.captchas = captchas;
            Random random = new Random();
            int place;
            if (String.IsNullOrEmpty(findusers))
            {

                captchasmodel.captchas = db.captchas.Where(x => x.imageComplex.Value == 2).ToList();

                int randomNumber = random.Next(0,captchasmodel.captchas.Count);
                place = randomNumber;
            }
            else
            {

                captchasmodel.captchas = db.captchas.Where(x => x.imageComplex.Value==1 ).ToList();

                int randomNumber = random.Next(0, captchasmodel.captchas.Count);
                place = randomNumber;
            }
            // return model to the view
            var selectedcaptcha = new CaptchaDisplayModel();
            selectedcaptcha.captchas = captchasmodel.captchas[place];
            return View("CaptchaShow",selectedcaptcha);
        }
 //
 // GET: /UserValidate/
 public ActionResult Index()
 {
     var users = db.users.ToList();
     var model = new UserValidateModel();
     model.users = users;
     return View();
 }