This is the first in a short series of posts to describe the new functionality found in XFA 3.0.
If you have developed a form with even modest complexity, you have almost certainly manipulated the presence property of fields, subforms and exclusion groups. With XFA 3.0 we have extended the possible values of this property to include "inactive".
The existing presence attribute can be one of these properties:
- visible – (default) Object is visible
- invisible – Object is invisible, but still participates in layout and event processing. i.e. space is allocated in the layout to display this object, its calculations and validations still fire.
- hidden – Object is invisible and excluded from layout. No space is reserved for this object. Its calculations and validations still fire.
In XFA 3.0 we now add:
- inactive – Object is hidden and excluded from event processing. Calculations, validations and other events do not fire.
A mortgage application form is sent to a client. The form has an optional section where the user may apply for mortgage life insurance. The life insurance application section is pre-populated with client information from the server. If the user chooses not to apply for life insurance:
- the optional section will remain hidden
- The calculation and validation scripts in the optional section will not fire
- Other event scripts such as layout:ready, form:ready, prePrint, preSubmit etc. do not fire
- We do not check for mandatory fields
All these behaviours will be true as long as the subform that defines the life insurance application is set to presence="inactive".
Once the user checks the box to apply for insurance, we toggle the setting to presence="visible" and then that section of the form becomes fully functional.
The new behaviour for presence applies only to these container objects: subform, field, exclGroup. The presence attribute is also found on draw, fill, items, edge, border, caption and corner — however in these contexts it will not introduce any new behaviour. It will behave the same as "hidden".
The Deep End
In a previous post, I described the various stages of processing we go through when we open a form:
- Loading content
- Merging data with template (create Form DOM)
- Executing calculations and validations
- Layout (pagination)
The enumeration of the presence attribute determines which of these stages a form object will participate in:
- Loading content
- Merging data with template (create Form DOM) (visible, invisible, hidden, inactive)
- Executing calculations and validations (visible, invisible, hidden)
- Layout (pagination) (visible, invisible)
- Render (visible)