NerdDinner.Controllers.AccountController.ValidateRegistration C# (CSharp) Method

        private bool ValidateRegistration(string userName, string email, string password, string confirmPassword)
        {
            if (String.IsNullOrEmpty(userName)) {
                ModelState.AddModelError("username", Resources.Resources.YouMustSpecifyUsername);
            }
            if (String.IsNullOrEmpty(email)) {
                ModelState.AddModelError("email", Resources.Resources.YouMustSpecifyEmailAddress);
            }
            if (password == null || password.Length < MembershipService.MinPasswordLength) {
                ModelState.AddModelError("password",
                    String.Format(CultureInfo.CurrentCulture,
                          Resources.Resources.YouMustSpecifyLongerPassword,
                         MembershipService.MinPasswordLength));
            }
            if (!String.Equals(password, confirmPassword, StringComparison.Ordinal)) {
                ModelState.AddModelError("_FORM", Resources.Resources.NewPasswordAndConfirmationMismatch);
            }
            return ModelState.IsValid;
        }