Enabling/disabling XForms triggers with XSLT

I ran into a issue today on how to enable/disable XForms triggers in a table generated by an XSLT sheet. The usual trick used in an XForms page has to be adapted slightly. So here it is:

First, define an XForms instance to hold "bind" targets for your trigger:

<xf:instance id="control-instance">
<control xmlns="">
<disabled-trigger />
<enabled-trigger />
</control>
</xf:instance>

Then, define a couple of "binds" as such:

<xf:bind nodeset="instance('control-instance')">
<xf:bind nodeset="disabled-trigger" readonly="true()" />
<xf:bind nodeset="enabled-trigger" readonly="false()" />
</xf:bind>

You now have two "binds" that you can use in @ref value of your triggers. This is what I do in the following snippet. I use an xsl:variable and an XPath conditional expression to hold the node name that I later use in the xf:trigger@ref.

<xsl:variable name="trigger-ref"
select="if(wo:StatusLog/wo:Status[last()][@code='ASSIGNABLE'])
            then 'enabled-trigger'
            else 'disabled-trigger'" />
<xf:trigger appearance="minimal"
ref="instance('control-instance')/{$trigger-ref}">
<xf:label>
<img class="{$trigger-ref}" src="/images/assign.png"
title="{{instance('i18n')/workOrderList/action/assign/hint}}" />
</xf:label>
<xf:action ev:event="DOMActivate">
<xf:setvalue ref="instance('selected-workorder')/@id">
<xsl:value-of select="@id" />
</xf:setvalue>
<xf:send submission="assign-workorder-submission" />
</xf:action>
</xf:trigger>

Note that as a display enhancement, I defined a CSS class for the "disabled" image. It has the same name as the element used for the trigger@ref which is a convenient shortcut.

<style>
.disabled-trigger {opacity: 0.4;}
</style>

This technique can be used very generically as one can see.

So long,

Laurent

Note: This was implemented with Orbeon and not tested anywhere else.