Lesson X.               Horizontal and Vertical Scrollbars

 

Objectives

ü       To be able to use Horizontal and Vertical Scrollbar controls to select from ranges of values.

ü       To be able to use Scrollbars to manipulate other controls.

 

 

 

Scrollbars let users control value changes.  Rather than type specific values, the user can move the scrollbar with the mouse to specify relative positions within a range of values.  There are two types of scrollbars: Horizontal and Vertical Scrollbars.  Except for their orientation, they share exactly the same properties.

 

 

 

 

 

 

	Example of a Horizontal Scrollbar (Left) and a Vertical Scrollbar (Right)

 

 

 

The following are the fundamental properties of a scrollbar.

 

Property	Description
LargeChange	Specifies the amount that the scrollbar’s Value property changes when the user clicks within the scrollbar’s shaft area.
Max	Indicates the maximum number of units that the scrollbar value represents at its highest setting.  The range is from 1 to 32,767 (the default Max value)
Min	Indicates the minimum number of units the scrollbar value represents at its lowest setting. The range is from 1 (the default Min value) to 32,767.
SmallChange	Specifies the amount that the scrollbar’s Value property changes when the user clicks an arrow at either end of the scrollbar.
Value	Contains the units of measurement currently represented by the position of the scrollbar.

 

When you place a scrollbar on a Form, set the range of values the scrollbar is to represent.  Set the Min and Max property to the lowest and highest value the scrollbar will represent, respectively.   When the user eventually clicks any arrow in the scrollbar, the Value of the scrollbar will change (positive SmallChange when the right or up arrow is clicked; negative SmallChange when the left or down arrow is clicked).

 

 

 

Let’s use the ScrollBar in a simple application.  In the Form below, the ScrollBar will be used to manipulate the font size of the Label.  The main task is simply to associate the Value property of the scrollbar to the FontSize property of the Label.  Thus, changing the ScrollBar’s Value will subsequently change the FontSize of the Label.

 

 

 

 

 

 

 

 

 

 

 

 

 

1.   Create the Form displayed above.

1.       Drag a Label control to the Form and set the following properties:

§         Name                            lblBanner

§         Caption                         Visual Basic

§         FontSize                        8

§         FontStyle                       Arial

§         BackColor                      Yellow

 

2.       Drag a HScrollBar to the Form and set the following properties:

§         Name                            hsbFSize

§         Min                               8

§         Max                              35

§         Value                            8

The Max value also determines the maximum font size of the label.  Tip: Assign the maximum font size of the caption that can fit within the Label to the Value property of the HScrollBar.  The initial value of the Value property should match the initial FontSize of the Label’s caption.

 

3.       Write the following procedure:

 

Private Sub hsbFSize_Change()

    LblBanner.FontSize = hsbFSize.Value

End Sub

4.       Run your application.

5.       Save your work as Lesson10.vbp.

 

 

 

 

 

1.       Create a program that manipulates the position of the Label in the Form using Vertical and Horizontal Scrollbars.  Note: Make sure that the Label does not go beyond the rectangular Shape control.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2.       Modify the program you have made in the Lesson in Action section.  Display the current font size in a Label.