Page 329 - Microsoft Office Excel 2003 Programming Inside Out

Developing Class Modules

Set ObjectVariable1 = New MyClass
Set ObjectVariable2 = ObjectVariable1
Set ObjectVariable1 = Nothing

Objects with Multiple Object Variables

It’s important to keep in mind that an object is not the same thing as an object variable. For
example, the following code creates an object, which has two variables pointing to it:

Set ObjectA = New MyClass
Set ObjectB = ObjectA
The first Set statement creates a new instance of MyClass, whereas the second Set statement Chapter 14
merely creates a second pointer to the same object created by the first statement.

This means that the following statements will do the same thing because both ObjectA and
ObjectB point to the same object:

ObjectA.Name = “Roses"
ObjectB.Name = “Roses”

If this isn’t confusing enough, executing the following statement will not destroy the object.

Set ObjectA = Nothing
Because ObjectB still points to the object, it will remain in memory until ObjectB is also set
to Nothing.

Properties, Methods, and Events

Associated with every object is a collection of properties, methods, and events, which are
used to communicate information between the object and the routine that created the object.

Public vs. Private Properties, Methods, and Events

The individual parts of a class can be labeled as either Public or Private. Anything marked as
Public is visible to anyone using the class, whereas anything marked as Private can be accessed
only from the code within the class.

Tip Don’t Rely on Defaults
Always explicitly mark everything within a class as either Public or Private, so you never
have to worry about whether something defaulted to Public or Private.

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Part 4: Advanced VBA