ON CHANGE block
The ON CHANGE block can be used to detect when a field has
been changed by user input. The ON CHANGE block is executed if the value has
changed since the field got the focus and if the modification flag is set.
The ON CHANGE block can be used in INPUT, INPUT
ARRAY and CONSTRUCT dialogs.
For editable fields defined as EDIT, TEXTEDIT
or BUTTONEDIT, the ON CHANGE block is executed when leaving a
field, if the value of the specified field has changed since the field got the focus and if
the modification flag is set for the field. You leave the field when you validate the dialog, when
you move to another field, or when you move to another row in an INPUT ARRAY.
However, if the text edit field is defined with the COMPLETER attribute to enable autocompletion, the ON CHANGE
trigger will be fired after a short period of time, when the user has typed characters in.
For editable fields defined as CHECKBOX,
COMBOBOX, DATEEDIT,
DATETIMEEDIT, TIMEEDIT,
RADIOGROUP, SPINEDIT,
SLIDER or URL-based WEBCOMPONENT (when the
COMPONENTTYPE attribute is not used), the ON
CHANGE block is invoked immediately when the user changes the value
with the widget edition feature. For example, when toggling the state of a
CHECKBOX, when selecting an item in a
COMBOBOX list, or when choosing a date in the calendar of a
DATEEDIT. Note that for such item types, when ON
CHANGE is fired, the modification flag is always set.
ON CHANGE order_checked -- Defined as CHECKBOX
CALL setup_dialog(DIALOG)ON CHANGE block and AFTER FIELD block are defined
for a field, the ON CHANGE block is executed before the AFTER
FIELD block.When changing the value of the current field by program in an ON
ACTION block, the ON CHANGE block will be executed when leaving the field
if the value is different from the reference value and if the modification flag is set (after
previous user input or when the touched flag has been changed by program).
In an INPUT or INPUT ARRAY, the field value change is related
to the value of the variable bound to the field. In a CONSTRUCT dialog, the field
value change is related to the input buffer / displayed value.
NEXT FIELD instruction, the comparison value is reassigned as
if the user had left and reentered the field. Therefore, when using NEXT FIELD in
ON CHANGE block or in an ON ACTION block, the ON
CHANGE block will only be invoked again if the value is different from the reference value.
This prevents field validation in ON CHANGE blocks; you must do validations in
AFTER FIELD blocks and/or AFTER INPUT blocks.