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' Exercise 9.3 Solution: Invoice.vb ' Invoice class. Public Class invoide ' declare variables for Invoice object Private partNumberValue As Integer Private partDescriptionValue As String Private quantityValue As Integer Private priceValue As Decimal ' four-argument constructor Public Sub New(ByVal part As Integer, ByVal description As String, ByVal count As Integer, ByVal pricePerItem As Decimal) PartNumber = part PartDescription = description Quantity = count Price = pricePerItem End Sub ' New ' property for partNumberValue; no validation necessary Public Property PartNumber() As Integer Get Return partNumberValue End Get Set(ByVal value As Integer) partNumberValue = value End Set End Property ' PartNumber ' property for partDescriptionValue; no validation necessary Public Property PartDescription() As String Get Return partDescriptionValue End Get Set(ByVal value As String) partDescriptionValue = value End Set End Property ' PartDescription ' property for quantityValue; ensures value is positive Public Property Quantity() As Integer Get Return quantityValue End Get Set(ByVal value As Integer) If value > 0 Then ' determine whether quantity is positive quantityValue = value ' valid quantity assigned End If End Set End Property ' Quantity ' property for pricePerItemValue; ensures value is positive Public Property Price() As Decimal Get Return priceValue End Get Set(ByVal value As Decimal) If value > 0 Then ' determine whether price is positive priceValue = value ' valid price assigned End If End Set End Property ' Price ' return String containing the fields in the Invoice in a nice format Public Overrides Function ToString() As String ' left justify each field, and give large enough spaces so all the columns line up Return String.Format("{0,-5} {1,-20} {2,-5} {3,6:C}", PartNumber, PartDescription, Quantity, Price) End Function ' ToString End Class ' Invoice ' ************************************************************************** ' * (C) Copyright 1992-2009 by Deitel & Associates, Inc. and * ' * Pearson Education, Inc. All Rights Reserved. * ' * * ' * DISCLAIMER: The authors and publisher of this book have used their * ' * best efforts in preparing the book. These efforts include the * ' * development, research, and testing of the theories and programs * ' * to determine their effectiveness. The authors and publisher make * ' * no warranty of any kind, expressed or implied, with regard to these * ' * programs or to the documentation contained in these books. The authors * ' * and publisher shall not be liable in any event for incidental or * ' * consequential damages in connection with, or arising out of, the * ' * furnishing, performance, or use of these programs. * ' **************************************************************************
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