n this exercise, you$$ll add two classes to the Inventory Maintenance application that inherit

the InvItem class. Then, you$$ll add code to the forms to provide for these new classes.

$1.$ Open the attached project. Then, review the code for the New Item form to see that the

items in the combo box and the label for the combo box depend on which radio button is

selected.

$2.$ Display the InvItem Class and modify the GetDisplayText method so it$$s overridable.

$3.$ Add a class named Plant that inherits the InvItem class. This new class should add a

string property named Size. It should also provide a default constructor and a constructor

that accepts four parameters $($item number, description, price, and size$)$ to initialize the

class properties. This constructor should call the base class constructor to initialize the

properties defined by that class. Finally, this class should override the GetDisplayText

method to add the size in front of the description, as in this example:

$32456491$ gallon Agapanthus $($$$7\mathrm{.}95)$

$4.$ Add another class named Supply that inherits the InvItem class and adds a string property

named Manufacturer. Like the Plant class, the Supply class should provide a default

constructor and a constructor that accepts four parameters, and it should override the

GetDisplayText method so the manufacturer is added in front of the description like this:

$9210584$ Ortho Snail pellets $($$$12\mathrm{.}95)$

$5.$ Modify the event handler for the Click event of the Save button on New Item form so it

creates a new item of the appropriate type using the data entered by the user.

$6.$ Test the application by adding at least one of each type of inventory item.