Powerful PowerPoint for Educators: Using Visual Basic for Applications to Make PowerPoint Interactive

myPhoneBook.thick 
ness
or I might want to add two thicknesses together to get something tall enough for
my daugh ter to sit on and be able to reach the table:
myPhoneBook.thickness + myNeighborsPhoneBook.thick 
ness
Finally, we turn to in heritance, and then you won’t be an ex pert in OOP, but 
you will be able to play one on TV. We have been look 
ing at the class
PhoneBook
. Well, is n’t a phone book just a spe cific type of book? Therefore,
we could think of a
PhoneBook
as a type of 
Book
that in herits all the prop erties
and methods from books. The ob ject I am work ing with is still
myPhoneBook
,
but it is not only a member of the class
PhoneBook
, it is (since 
PhoneBook
is a
sub class of
Book
) also a mem ber of the class
Book
. Ev erything you can do with
a book, in general, you can do with a phone book . . . and more. For example, you 
can turn pages in a book, look at the cover, weigh down pa pers, etc. You can also
look up a phone num ber or find in formation about area codes in a phone book,
but not in all books.
Now, with this ba sic un derstanding of ob jects, classes, and methods, you
will be able to un derstand the basics of OOP when these terms come up.
Before leaving OOP, think about how it re lates to PowerPoint. PowerPoint
has many ob jects and classes. A typical PowerPoint presentation con tains many
36 In tro duc ing Vi sual Ba sic for Ap pli ca tions

---

slides. Slides! That’s a class. As a class,
Slides
is the col lection of all the in di-
vidual slides in a presentation. The set of slides in your specific presentation is
an ob ject. That set of slides con tains in dividual slides. A slide might con tain
many ob jects or shapes. Think about a slide with a text box, a piece of clip art,
and a button. Perhaps these are shapes 1, 2, and 3 on the slide. They each have
many properties, such as whether or not they are vis ible. Because a text box, a
piece of clip art, and a button are all mem bers of the class