Tscrollbar of VCL Components

The inheritance relationships of the tscrollbar class are as follows:

In many cases, you do not need to add a scroll bar to the control. When the control cannot be displayed, the control selects whether to add a scroll bar based on its settings. If you want to control the scrolling of controls on the form, you need to use the scrollbar component located on the standard component panel. Common attributes of the scrollbar component are listed below.

Common attributes of tscrollbar

Attribute	Description
Kind	The direction of scrolling. Two options are available: sbhorizontal and sbvertical.
Largechange	Specifies the scroll distance of the slider when you press the flip key on the keyboard or click the blank position on the scroll bar.
Max	The position at the end of the scroll bar in numbers
Min	Position of the scroll bar header in numbers
Pagesize	Specify the size of the slider (in the same unit as the max and Min attributes)
Position	Initial Position of the slider
Smallchange	Specifies the scroll distance of the slider when you press the arrow key on the keyboard or click the arrow button on the scroll bar.

The max and Min attributes determine the range of the position attribute. For example, if the min value is 0 and the max value is 100, the entire scroll bar is divided into 100 equals points. The value of the position attribute can only be within the range of 0 to 100. If the largechange attribute is 10, smallchange is 2. Use the direction key. It takes 50 times to move the slider from one end to the other. Instead, use the flip key, which can be completed only 10 times.

The main events of tscrollbox are as follows:

• Onscroll-triggered when you scroll the scroll bar with a keyboard or mouse.
• Onchange -- triggered when the position attribute of the scrollbar control is changed. If you scroll the scroll bar, the event is triggered immediately after the onscroll event.