/// <summary>
        /// Event handler for when the user clicks the finish button on the wizard.
        /// Checks to see if the customer record already exists, and if it does not, add the user to the database.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        protected void Wizard1_FinishButtonClick(object sender, WizardNavigationEventArgs e)
        {
            //Creates a new customer object from the information entered into the wizard.
            var customer = new Customer
            {
                FirstName = txtFirstName.Text,
                LastName  = txtLastName.Text,
                Phone     = txtPhone.Text,
                City      = txtCity.Text
            };

            //Checks to see if the user is already registered. If they are, prevent them from registering again.
            if (AuthManager.Exists(customer.FirstName, customer.LastName, customer.Phone, customer.City))
            {
                //Model state belongs to the page, not the user control. Have to declare Page.ModelState
                Page.ModelState.AddModelError("", "A record for this customer already exists. Please sign in with your information.");
            }

            else
            {
                //Pass the new customer object to the authentication manager to insert in to DataContext.
                AuthManager.Add(customer);

                //Redirect the user to a confirmation page.
                Response.Redirect("~/Confirm");
            }
        }