public void Save()
        {
            Account account = new Account()
            {
                FirstName   = FirstName,
                LastName    = LastName,
                PhoneNumber = PhoneNumber
            };

            if (Id.HasValue)
            {
                AccountsModel.UpdateAccount(Id.Value, account);
            }
            else
            {
                AccountsModel.CreateAccount(account);
            }
            closeWindow();
        }