The square bracket ([ ]) notation denotes
the occurrence value of an object.
In language-specific forms for Arabic, Hebrew, Thai, and Vietnamese,
the reference syntax is always on the right (even for right-to-left
languages).
ExampleTo
construct an occurrence value reference, place square brackets ([ ])
after an object name, and enclose within the brackets one of the
following values:
[ n ], where n is
an absolute occurrence index number beginning at 0. An occurrence
number that is out of range does not return a value. For example,
xfa.form.form1.#subform.Quantity[3]
refers
to the fourth occurrence of the Quantity object.
[ +/- n ], where n indicates
an occurrence relative to the occurrence of the object making the
reference. Positive values yield higher occurrence numbers, and
negative values yield lower occurrence numbers. For example,
xfa.form.form1.#subform.Quantity[+2]
This
reference yields the occurrence of Quantity whose occurrence number
is two more than the occurrence number of the container making the
reference. For example, if this reference was attached to the Quantity[2]object
, the reference would be the same as
xfa.template.Quantity[4]
If
the computed index number is out of range, the reference returns
an error.
The most common use of this syntax is for locating
the previous or next occurrence of a particular object. For example,
every occurrence of the Quantity object (except the first) might
use Quantity[-1] to get the value of the previous Quantity object.
[*] indicates multiple occurrences of an
object. The first named object is found, and objects of the same
name that are siblings to the first are returned. Note that using
this notation returns a collection of objects. For example,
xfa.form.form1.#subform.Quantity[*]
This expression refers to all objects with a name ofQuantitythat
are siblings to the first occurrence ofQuantityfound
by the reference.
Using
the tree for reference, these expressions return the following objects:
Subform_Page.Subform1[*]returns
bothSubform1objects.
Subform_Page.Subform1.Subform3.TextField2[*]returns twoTextField2objects.Subform_Page.Subform1resolves
to the firstSubform1object
on the left, andTextField2[*]evaluates
relative to theSubform3object.
Subform_Page.Subform1[*].TextField1 returns
both of theTextField1instances.Subform_Page.Subform1[*]resolves
to bothSubform1objects,
andTextField1evaluates
relative to theSubform1objects.
Subform_Page.Subform1[*].Subform3.TextField2[1]returns the
second and fourthTextField2objects
from the left.Subform_Page.Subform1[*]resolves
to bothSubform1objects, andTextField2[1]evaluates
relative to theSubform3objects.
Subform_Page.Subform1[*].Subform3[*]returns
both instances of theSubform3object.
Subform_Page.*returns bothSubform1objects
and theSubform2object.
Subform_Page.Subform2.*returns
the two instances of theNumericField2object.
You can use the ‘ [ ]’ (square bracket)
syntax with JavaScript if it used with the resolveNode method.
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