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 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 the modification flag is set for the field. The field is left when user validates the dialog, when moving to another field, or when moving 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)

When changing by program the value of the current field in an ON ACTION block, the ON CHANGE block will be executed when leaving the field, if the value is different from the previous value and 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.