A subform is a section in the form design
that provides anchoring, layout, and geometry management for objects.
The objects in a subform can be arranged in rows, columns, or some
other kind of balanced arrangement.
More than one subform can be used in a form design. Subforms
can be placed inside other subforms. This relationship is displayed
in the Hierarchy palette.
Subforms are used to organize a form into different sections.
They can also be used to create a form that contains sections that
automatically expand and shrink to accommodate the data. If you
set a subform to grow, the layout of the form changes in response
to the amount of data that is merged when the form is rendered.
When the data is merged, subforms ensure that objects and their
data are positioned consistently relative to each other. Subforms
can be used to match the data hierarchy in XML data.
If you are designing a form that has a fixed layout, it is unlikely
that you will need to work with more than one subform because the
default subform positions the objects automatically.
You can manipulate the properties of a subform in the Subform
and Binding tabs of the Object palette. You can define these properties:
Give a meaningful name to the subform (recommended)
Enable the subform to span page breaks or force it to be
rendered on the next page when the data is merged
Specify whether to place the subform after the previous subform,
in the specified content area, or on a page that is formatted according
to the specified master page
Specify whether to place the subform in the same content
area as the previous or next subform
Specify the flow order of merged data after the subform is
placed.
Define the subform as visible, invisible, or hidden
Specify a locale for the subform
Specify whether the subform will repeat its objects each
time a unique data item is provided for one of its objects
If required, create an overflow leader or trailer for a subform
that is capable of repeating the rendering of its objects
Specify a binding method for controlling how the subform’s
objects are mapped to data
All forms contain a root (parent) subform. In the Hierarchy palette,
the root subform (form1) is displayed as the top-level node with
the default page subform (untitled Subform) appearing as a child
node below the root subform.
Designer automatically adds to every page a default subform that
covers the whole page, and corresponds in size and position to the
default content area on the master page. Any subforms that you subsequently
add to the pages are nested in and appear below the default page
subform in the Hierarchy palette.
In the Hierarchy palette, each subform is represented by a node,
and the objects wrapped in a subform are displayed under the subform
node. The children of the subform do not inherit changes made on
the subform level; the properties of each object must be defined
individually.
If you look at the Purchase Order sample, the root subform, form1,
is shown as the top-level node with the default page subform, purchaseOrder,
appearing below as a child of the root subform. The other subforms
used to wrap objects on the page (header, detailHeader, detail,
and total) are nested under the page subform. In the Hierarchy palette,
each subform is represented by a node, and the objects wrapped in
a subform are displayed under each node.
