Word Document Properties

Figure 9-1:
Use the
Debugger 
to see
predefined
collections.
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Part III: Expanding Your VBA Horizons 
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Defining Your Own Data Types
A VBA 
user-defined data type
is nothing more than a list (collection) of data
elements that you want to use together. You aren’t really creating a new data
type — at least not one that you could identify as a unique entity, such as a
String
or an 
Integer
. In this section, I show how to benefit from user-
defined data types and demonstrate their use.
Understanding user-defined data types
Creating a user-defined type means defining the data that you want to use
together and deciding which native data types work best. The example in the
earlier “Adding keyed data to the collection” section uses a database connec-
tion to get hold of data and place it in a collection. The implementation (the
actual coding) in that example is difficult because you have to make three
entries in the collection for each database record. Here’s a user-defined type
that places all the information in one entry. (You can find the source code for
this example on the Dummies.com site at 
http://www.dummies.com/
go/vbafd5e
.)
‘ Define a user type.
Public Type APerson
Name As String ‘ The person’s name.
Telephone As String ‘ The contact telephone number.
LastContact As Date ‘ The date of last contact.
End Type
You create a user-defined type by using the 
Type
keyword followed by the
name of the new data type. The structure contains native data types. Each
Figure 9-2:
Browse 
for the
collections
that you
need to use
in your
program.
221