Computer Programming Concepts and Visual Basic David I. Schneider

298 Computer Programming Concepts and Visual Basic
EXAMPLE 4
The following program allows the user to select the text size in a text box. The three option buttons have
been attached to the frame with the single-click-draw technique.
Private Sub opt12pt_Click()
txtInfo.Font.Size = 12
End Sub
Private Sub opt18pt_Click()
txtInfo.Font.Size = 18
End Sub
Private Sub opt24pt_Click()
txtInfo.Font.Size = 24
End Sub
Object Property Setting
frmSize Caption Change Size
fraFontSize Caption Font Size
opt12pt Caption &12
opt18pt Caption 1&8
opt24pt Caption &24
txtInfo Text Hello
[Run, and click on the last option button (or press Alt+2).]
A single form can have several groups of option buttons. However, each group must be
attached to its own frame or picture box, or to the form itself.
THE HORIZONTAL AND VERTICAL SCROLL BAR CONTROLS
Figure 10-4 shows the two types of scroll bars. When the user clicks on one of the arrow buttons,
the thumb moves a small amount toward that arrow. When the user clicks between the
thumb and one of the arrow buttons, the thumb moves a large amount toward that arrow. The
user can also move the thumb by dragging it. The main properties of a scroll bar control are
Min, Max, Value, SmallChange, and LargeChange, which are set to integers. At any time,
hsbBar.Value is a number between hsbBar.Min and hsbBar.Max determined by the position of
the thumb. If the thumb is halfway between the two arrows, then hsbBar.Value is a number
halfway between hsbBar.Min and hsbBar.Max. If the thumb is near the left arrow button, then
hsbBar.Value is an appropriately proportioned value near hsbBar.Min. When an arrow button
is clicked, hsbBar.Value changes by hsbBar.SmallChange and the thumb moves accordingly.
When the bar between the thumb and one of the arrows is clicked, hsbBar.Value changes by
hsbBar.LargeChange and the thumb moves accordingly. When the thumb is dragged,