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Version: 11.2

Actions, events and triggers

Actions and events​

In USoft Windows Designer, you can script customised software behaviour by triggering actions when events occur. For example:

  • You can open or close info boxes or dialogs when the end user clicks certain buttons.
  • You can change the background color of a field when it displays certain data.
  • You can have totals re-computed in additional fields each time new data are displayed.
  • You can raise a particular tab page in a Tab object displaying child data, depending on what data are displayed in a parent box.

Triggering object and target object​

Actions are defined on objects. Events are also defined on objects. Each time you script an action that must occur on an event, there is a source object or triggering object where the event takes place, and a target object where the action must have an effect. For example, if you want data to be cleared from an info box when the user presses a button, the button is the source object and the info box is the target object.

The triggering object is implicitly the object where the event is defined. If you script:

RecordDelete()

in the Action event property of a button B, then the triggering object is button B.

The target object is often also implicit. In an info box, the target object of RecordDelete() is by default the top-level info box that displays the data. This is where a record is deleted.

At other times, you specify the target object explicitly.

Tab_1.ControlSetActiveTab(Page 2)

the target object is "Tab_1". This is the tab control that must execute the action of raising its Page 2 as the active tab page.

Conditional events​

In some cases, you want the script to take effect only under specific conditions. For example, you want to delete a record when the user presses a button, but this may ONLY happen if the CANCEL_DATE field in the record has a non-null value.

To script conditional actions, you must have records to decisions. A decision allows you to find out first whether something applies, and then IF it applies to perform an action (called Yes Action). A decision also lets you define what action must be taken in the opposite case (the decision's No Action).