public void button2_Click(object sender, EventArgs e) // Retrieve Button on click event { // selecting or typing a valid order id and displaying the results try { int orderID = Convert.ToInt32(cborderId.Text); Orders myOrder = OrdersDB.GetOrders(orderID); List <OrderDetails> myOrderDetails = OrderDetailsDB.GetOrderDetails(orderID); if (Object.Equals(myOrder, null)) // if ordr id not valid, show the follofing message { MessageBox.Show("No matching Order Id's found, please provide a valid Order ID", "Order ID Error"); } else // else display all the fields and read only order details data grid form { displayOrder(myOrder); displayOrderDetails(myOrderDetails); calculateTotalprice(); } } catch (FormatException) // catching the wrong format order id exception, in case user types an alphabet or anything other than the valid id { MessageBox.Show("Select from the drop down list and Retrieve.", "Input Error"); } }
private void calculateTotalprice() // calculating the total price for all the orders associated with one order id { int orderID = Convert.ToInt32(cborderId.Text); List <OrderDetails> myOrderDetails = OrderDetailsDB.GetOrderDetails(orderID); double totalPrice = 0; double UnitPrice = 0; int Quantity = 0; double Discount = 0; foreach (OrderDetails d in myOrderDetails) // calculating by going through each order details rows { UnitPrice = d.UnitPrice; Quantity = d.Quantity; Discount = d.Discount; totalPrice += UnitPrice * (1 - Discount) * Quantity; } lblTotalPrice.Text = totalPrice.ToString("c"); // displaying the result in the text field in a currency format }