XForms Essentials

Repeating Line Items

One of the most sorely missed features in HTML forms comes by many names: tables, grid controls, or line items. The basic concept is that many forms in common use don’t fit in well with a flat list of form controls. Figure 6-11 shows one embodiment of this, rendered in the X-Smiles browser.

Figure 6-11. Repeating line items in X-Smiles

Another common scenario is a purchase order, with repeating lines, each containing quantity, description, price, and computed extended price.

repeat

The primary means of accomplishing this in XForms is the repeat element, which operates over homogeneous collections, the same as itemset, described earlier. The nodeset attribute of repeat selects a number of nodes, and the contents of the element, both from XForms and from the host language, are effectively repeated once for each resulting node. One way to think of this is to “unroll” the repeat, so that the following:

<repeat nodeset="item">
  <input ref="@quantity" .../>
</repeat>

has a similar effect, when the nodeset returns three item nodes, to:

<input ref="item[1]/@quantity" .../>
<input ref="item[2]/@quantity" .../>
<input ref="item[3]/@quantity" .../>

The main difference between a repeat element and unrolled syntax (besides convenience) is how the result is presented to the user. The repeat version makes it possible to show more items in a limited space, as in the case of scroll ...