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<< Click to Display Table of Contents >> Navigation: ThinBASIC Modules > UI (User Interface) > CONTROLS > Control Types > ScrollBar Control > ScrollBar Control Creation > CONTROL ADD SCROLLBAR |
Description
Add a scrollbar control inside a dialog.
Syntax
hndl = CONTROL ADD SCROLLBAR [Name ControlName], hwnd, ctrlID, txt, xPos, yPos, Width, Height [, [Style] [, [ExStyle]]] [[,] CALL CallBack]
Returns
Number
Control window handler.
Parameters
Name |
Type |
Optional |
Meaning |
ControlName |
String |
Yes |
Optional name for the control.
This name must be globally unique, and is used to create a global variable to be used with control name methods and properties. |
hwnd |
Number |
No |
Handle of the dialog containing the control |
ctrlID |
Number |
No |
Control identifier |
txt |
String |
No |
A text expression representing the text you want to assign to the control. |
xPos |
Number |
No |
Horizontal position of the control inside the dialog |
yPos |
Number |
No |
Vertical position of the control inside the dialog |
Width |
Number |
No |
Control width |
Height |
Number |
No |
Control height |
Style |
Number |
Yes |
Primary style of the control. See SCROLLBAR Style equates. |
ExStyle |
Number |
Yes |
Extended style of the control. See SCROLLBAR ExStyle equates. |
CallBack |
Function |
Yes |
Optional name of a Callback Function that receives all %WM_COMMAND and %WM_NOTIFY messages for the control.
If the Callback Function processes a message, it should return %TRUE (non-zero) to prevent the message being passed unnecessarily to the dialog callback (if one exists).
The dialog callback should also return %TRUE if the notification message is processed by that Callback Function. |
Remarks
If the ampersand (&) character appears in the txt parameter, the letter that follows will become a control accelerator (hot-key) to enable the user to directly select the scroll bar control, simply by pressing and holding the ALT key while pressing the specified hot-key. For example, "&5" makes ALT+5 the hot-key. The actual text in txt is not displayed in a scroll bar control.
When the user clicks on a scroll bar, drags the thumb (also called the scroll box), or initiates a scroll event with the keyboard, a message is sent to the Callback Function designated for the control. If there is no Callback Function designated, the message is sent to the callback for the dialog.
| %WM_HSCROLL | Sent when the user adjusts a horizontal scroll bar. |
| %WM_VSCROLL | Sent when the user adjusts a vertical scroll bar. |
When a Callback Function receives a %WM_COMMAND message, it should explicitly test the value of CBCTL and CBCTLMSG to guarantee it is responding appropriately to the notification message.
When a Callback Function receives a %WM_HSCROLL or %WM_VSCROLL message, it should retrieve and set the scroll bar control settings through the GetScrollInfo and SetScrollInfo API function calls or using thinBasic functions dedicated to Scrollbar control. Be sure to use the %SB_CTL flag with these API functions, rather than the %SB_HORZ or %SB_VERT flags. See SCROLLINFO structure info.
Upon creation, a scrollbar has the following setup:
•lower limit = 0
•upper limit = 100
•page size = 10
•current position = 0
Restrictions
See also
Scrollbar control specific functions
Examples