/// <summary> /// Allows admin user to view the sum of all sold books /// </summary> /// <param name="adminId"></param> private void ViewTotalIncome(int adminId) { WebbShopAPI api = new WebbShopAPI(); var totalIncome = api.MoneyEarned(adminId); if (totalIncome != 0) { AdminView.DisplayMoneyEarned(totalIncome); return; } MessageViews.DisplayErrorMessage(); }