Computer Programming Concepts and Visual Basic David I. Schneider

288 Computer Programming Concepts and Visual Basic
adds str to the list. The item is added at the proper sorted position if the Sorted property is True,
and otherwise is added to the end of the list. At any time, the value of
lstBox.ListCount
is the number of items in the list box.
Each item in lstBox is identified by an index number ranging from 0 through
lstBox.ListCount – 1. The value of
lstBox.NewIndex
is the index number of the item most recently added to lstBox by the AddItem method. During
run time you can highlight an item from a list by clicking on it with the mouse or by moving
to it with the up- and down-arrow keys when the list box has the focus. (The second method
triggers the Click event each time an arrow key causes the highlight to move.) The value of
lstBox.ListIndex
is the index number of the item currently highlighted in lstBox. (If no item is highlighted, the
value of ListIndex is –1.)
The string array lstBox.List( ) holds the list of items stored in the list box. In particular,
the value of
lstBox.List(n)
is the item of lstBox having index n. For instance, the statement picBox.Print lstBox.List(0)
displays the first item of the list box lstBox. The value of
lstBox.List(lstBox.ListIndex)
is the item (string) currently highlighted in lstBox. Alternatively, the value of
lstBox.Text
is also the currently highlighted item. Unlike the Text property of a text box, you may not assign
a value to lstBox.Text.
The statement
lstBox.RemoveItem n
deletes the item of index n from lstBox, the statement
lstBox.RemoveItem lstBox.ListIndex
deletes the item currently highlighted in lstBox, and the statement
lstBox.Clear
deletes every item of lstBox.
EXAMPLE 1
An oxymoron is a pairing of contradictory or incongruous words. The following program displays a sorted
list of oxymorons. When you click an item (or highlight it with the up- and down-arrow keys), it is displayed
in a picture box. A command button allows you to add an additional item with an Input box. You
can delete an item by double-clicking on it with the mouse. (Note: When you double-click the mouse,
two events are processed—the Click event and the DblClick event.) After running the program, click on
different items, add an item or two (such as “same difference” or “liquid gas”), and delete an item.
Object Property Setting
frmOxyMor Caption OXYMORONS
lstOxys Sorted True
cmdAdd Caption Add an Item
lblDelete Caption [To delete an item,
double-click on it.]
picSelected