CHECKBOX item type
Defines a boolean or three-state checkbox field.
CHECKBOX item basics
The CHECKBOX
form item defines a field with a check box and a text label.
Defining a CHECKBOX
The TEXT
attribute defines the label to be displayed near the check
box. Consider using localized
strings for this attribute.
The box shows a check mark when the form field contains the value defined in the VALUECHECKED
attribute (for example: "Y"
), and shows no check mark if the field
value is equal to the value defined by the VALUEUNCHECKED
attribute (for example:
"N"
). If you do not specify the VALUECHECKED
or
VALUEUNCHECKED
attributes, they respectively default to
TRUE
(integer 1) and FALSE
(integer 0).
By default, during an INPUT
dialog, a CHECKBOX
field can have three states:
- Grayed (
NULL
value ) - Checked (
VALUECHECKED
value ) - Unchecked (
VALUEUNCHECKED
value )
If the field is declared as NOT NULL
, the initial state can be
grayed if the default value is NULL
; once the user has changed the state of the
CHECKBOX
field, it switches only between checked and unchecked states.
During a CONSTRUCT
, a CHECKBOX
field always
has three possible states (even if the field is NOT NULL
), to allow the end user to
clear the search condition:
- Grayed (No search condition)
- Checked (Condition column =
VALUECHECKED
value) - Unchecked (Condition column =
VALUEUNCHECKED
value)
Front-ends support different presentation and behavior options, which can be
controlled by a STYLE
attribute. For more details, see Style attributes common to all elements and CheckBox style attributes.
Detecting CHECKBOX modification
To inform the dialog immediately when the value changes, define an ON
CHANGE
block for the CHECKBOX
field. The program can then react
immediately to user changes in the field:
-- Form file (grid layout)
CHECKBOX cb1 = order.ord_valid,
ITEMS = ... ;
-- Program file:
ON CHANGE ord_valid
-- The checkbox field has been modified
For more details, see Reacting to field value changes.
Where to use a CHECKBOX
CHECKBOX
form item can be defined in different ways:- With an item tag and a CHECKBOX item definition in a
grid-layout container (
GRID
,SCROLLGRID
andTABLE
). - As a CHECKBOX stack item in a
STACK
container.