Introduction

This is an example that applies some features of the combo box control. We will simulate a small business that sells ice cream. An ice cream order is represented by a flavor, a type of container, an ingredient if any, and the number of scoops.

When a customer places an order, the clerk will select the date and the time the order was processed. Then the composition of the order as specified by the customer will also be selected. After making these selections, the employee will calculate the price of the order.

Prerequisites:

• Static Text
• Date Picker
• Time Picker
• Combo Box
• Button
• Dialog Box

Practical Learning: Starting the Exercise

1. Start Microsoft Visual C++
2. Create a new project named IceCream1
3. Create the project as a Dialog Based and set the Dialog Title as Clarksville Ice Cream
    
   
4. Click Finish and design the dialog box as follows:
    

   Control ID Caption Additional Properties Group Box         Static Text     Order Date:   DateTimePicker IDC_ORDERDATE   Format: Short Date Static Text     Order Time:   DateTimePicker   IDC_ORDERTIME   Format: Time Static Text     Flavor:   Combo Box   IDC_FLAVORS   Data: Vanilla;Cream of Cocoa; Chocolate Chip; Butter Pecan; Chocolate Cookie; Chunky Butter; Organic Strawberry;Chocolate Brownies; Caramel Au Lait Static Text     Container:   Combo Box   IDC_CONTAINERS   Data: Cone;Cup;Bowl Static Text     Ingredient:   Combo Box   IDC_INGREDIENTS   Data: None; Peanuts; Mixed Nuts; M & M; Cookies Static Text     Scoops:   Edit Control   IDC_SCOOPS   Align Text: Right Number: True Static Text     Order Total:   Edit Control   IDC_ORDERTOTAL   Align Text: Right Button   IDC_CALCULATE Calculate   Button   IDC_NEWORDER New Order   Button   IDCANCEL Close

5. Using either the ClassWizard or the Add Member Variable Wizard, add the following member variables to the controls:
    

   ID	Value Variable		Control Variable
   	Type	Name
   IDC_ORDERDATE			m_OrderDate
   IDC_ORDERTIME			m_OrderTime
   IDC_FLAVORS			m_Flavor
   IDC_CONTAINERS	CString	m_Container	m_ctlContainer
   IDC_INGREDIENTS			m_Ingredient
   IDC_SCOOPS	int	m_Scoops
   IDC_ORDERTOTAL	double	m_TotalOrder

6. On the dialog box, double-click the Calculate button and implement its event as follows:
    

   void CIceCream1Dlg::OnBnClickedCalculate() { // TODO: Add your control notification handler code here // The prices of the components of an ice cream order double PriceContainer = 0.00, PriceIngredient = 0.00, PriceScoops = 0.00; // The total price of the order double OrderTotal = 0.00; // Process an order only if the user had selected a flavor if( this->m_Flavor.GetCurSel() != -1 ) { // Start the price of an ice cream based on the type of container if( this->m_Container == "Cone" ) PriceContainer = 0.55; else if( this->m_Container == "Cup" ) PriceContainer = 0.75; else PriceContainer = 1.15; // Find out if the user selected an ingredient other than None if( this->m_Ingredient.GetCurSel() > 0 ) PriceIngredient = 0.95; // The number of scoops of this order // Set the default to 1 because a valid must have at least one int Scoops = 1; Scoops = this->m_Scoops; // Increase the price of the Ice Cream depending on the number of scoops if( Scoops == 2 ) PriceScoops = 2.25; else if( Scoops == 3 ) PriceScoops = 3.25; else PriceScoops = 1.85; // Calculate the total order OrderTotal = PriceScoops + PriceContainer + PriceIngredient; this->m_OrderTotal = OrderTotal; } else AfxMessageBox("You must select a flavor in order to process an order"); UpdateData(FALSE); }

7. Return to the dialog box. Double-click the New Order button and implement its event as follows:
    

   void CIceCream1Dlg::OnBnClickedNeworder() { // TODO: Add your control notification handler code here this->m_Flavor.SetCurSel(-1); this->m_ctlContainer.SetCurSel(-1); this->m_Ingredient.SetCurSel(-1); this->m_Scoops = 0; this->m_OrderTotal = 0.00; UpdateData(FALSE); }

8. Test the application
9. After using it, close it and return to your programming environment