programming-for-dummies

346
Using a Collection
Because a collection is nothing more than a data structure, like an array, the
first step to creating a collection is to declare a variable as a collection, such
as the following Visual Basic.NET example shows:
Dim MyStuff as New Collection
This command simply identifies a MyStuff variable as a collection data
structure. The New command tells the computer to create a new collection.
Adding data to a collection
When you first create a collection, it contains zero items. Each time you add
a new chunk of data to a collection, it expands automatically so you never
have to specify a size beforehand (like an array) or deliberately resize it later
(like a dynamic array).
To add data to a collection in Visual Basic.NET, you must use an Add command
like this:
Dim MyStuff as New Collection
MyStuff.Add (“Dirty socks”)
Each time you add another element to a collection, the computer tacks
that new data at the end of the collection. So if you added the string Dirty
socks, the number 7348, and the number 4.39, the collection would look like
Figure 3-1.
Figure 3-1:
Collections
expand
automatically
each
time you
store new
data.
1
Dirty socks Each time you add an item to a collection . . .
1 2
Dirty socks 7348 . . . the collection grows automatically.
1 2 3
Dirty socks 7348 4.39
Dim MyStuff as New Collection
MyStuff.Add (“Dirty socks”)
MyStuff.Add (7348)
MyStuff.Add (4.39)