CD Publisher
 

In this exercise, we will develop an application for a small CD publishing company. The owner wants the prices to be calculated so a customer would get a discount if he orders more. To attract customers and encourage them to order more, she has decided to fix the prices so that the customer would pay:

  • $20/CD if he orders less than 20 units
  • $15/CD if he orders less than 50 units
  • $12/CD if he orders less than 100 units
  • $8/CD if he orders less than 500 units
  • $5/CD if he orders more than 500 units
  1. Start Visual Studio
  2. Create a new Visual Basic Windows Application and name it CDPublisher
  3. Design the form as follows:
     
    CD Publisher Design
    Control Name Text Other Properties
    Label   Number of CDs:  
    NumericUpDown updQuantity   Maximum: 10000
    TextAlign: Center
    Label   Unit Price:  
    TextBox txtUnitPrice 0 TextAlign: Right
    Label   Total Price:  
    TextBox txtTotalPrice 0 TextAlign: Right
    Button btnClose Close  
  4. Double-click the Close button and implement it as follows:
      
    private void btnClose_Click (Object sender, System.EventArgs e)
	{
		Close();
	}
  5. Double-click the up down button to access its OnChange() event and implement it as follows:
      
    private void updQuantity_ValueChanged (Object sender, System.EventArgs e)
{
	int Quantity;
	double UnitPrice, TotalPrice;

	Quantity = System.Convert.ToInt32(updQuantity.get_Value());

	if( Quantity < 20 )
		UnitPrice = 20;
	else if( Quantity < 50 )
		UnitPrice = 15;
	else if( Quantity < 100 )
		UnitPrice = 12;
	else if( Quantity < 500 )
		UnitPrice = 8;
	else
		UnitPrice = 5;

	TotalPrice = Quantity * UnitPrice;
	txtUnitPrice.set_Text(String.Format("{0:C}", (System.Double)UnitPrice));
	txtTotalPrice.set_Text(String.Format("{0:C}", (System.Double)TotalPrice));
}
  6. Test the application
  7. Close it
 
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