How to do something with selected values of an xforms:select every time they change?

I have this problem with XForms I am running on Orbeon Forms. I am using a fr:box-select control as follows:

<fr:box-select bind="box-select-bind" id="box-select-control">
        <xforms:action ev:event="xforms-value-changed">
         <xxforms:variable name="selected-value" select="."/>
         <xforms:message level="modal">Hello:<xforms:output select="$selected-value" />
         </xforms:message>

        </xforms:action>

        <xforms:itemset nodeset="instance('codes')/box-select/item">
                                    <xforms:label ref="label"/>
                                    <xforms:value ref="value"/>
         </xforms:itemset>
   </fr:box-select>

The binding is to a simple XML file:

<box-results></box-results>

The codes XML looks like:

<box-select>
    <item>
        <label>Cat</label>
        <value>cat</value>
    </item>
    <item>
        <label>Dog</label>
        <value>dog</value>
    </item>
    <item>
        <label>Bird</label>
        <value>bird</value>
    </item>
    <item>
        <label>Fish</label>
        <value>fish</value>
    </item>
</box-select>

When I check entries in the box, my node <box-results> gets updated with the selected values separated by a space, which seems to be what is expected. However, I can't seem to find any documentation on how to process the selected values. I want to get access to what value was just selected, de-selected and use the value of this item in an xpath. So, if a value was selected then I would do this:

<setvalue
 ref="somexpath[id=$selected-value]/display
 value="'true'"/>

And if a value was deselected 开发者_C百科I would do this:

<setvalue
 ref="somexpath[id=$selected-value]/display
 value="'false'"/>

Basically, I just want to know the event to use, and how to get access to the value when it fires. Then I want to use this value in an xpath. I am going to use this to hide/display portions of the form. Using the xforms-value-changed event the Xpath "." doesn't return what I would expect, as it does in "select1" controls.

I can loop through all the values that are selected like so:

<xforms:action ev:event="xforms-select" xxforms:iterate="for $s in tokenize(instance('data-inst')/box-results,'\s')return xxforms:element('text',$s)">
    <xforms:message level="modal">Hello selected:<xforms:output select="$s" />
</xforms:action>

However, this isn't exactly what I need. I might be able to make this work, but it would require a lot more work because I need to do know what ones are deselected to change the display for the user.

Since in your case you don't need to know specifically which value changed, you can on value change reset all the values in somexpath[id=$selected-value] as needed. You can do this with the following code which uses just <xforms:setvalue> with an xxforms:iterate:

<xforms:action ev:event="xforms-value-changed">
    <xxforms:variable name="selected-values" select="tokenize(., '\s+')"/>
    <xforms:setvalue xxforms:iterate="instance('codes')/item" 
                     ref="@selected">false</xforms:setvalue>
    <xforms:setvalue xxforms:iterate="$selected-values"
                     ref="for $v in . return instance('codes')/item
                     [value = $v]/@selected">true</xforms:setvalue>
</xforms:action>

Also see the full source of an example that uses the above snippet.

you can use ev:event="xforms-select" and ev:event="xforms-deselect" events.

Also the selected value can be captured using event('xxforms:item-value')

Here is how it would be used in case anyone is wondering:

<xforms:action ev:event="xforms-select">
<xxforms:variable name="selected" select="event('xxforms:item-value')" />
<xforms:message level="modal">Select:<xforms:output value="$selected" /></xforms:message>
</xforms:action>

<xforms:action ev:event="xforms-deselect">
<xxforms:variable name="deselected" select="event('xxforms:item-value')" />
<xforms:message level="modal">deSelect:<xforms:output value="$deselected" />
</xforms:message>
</xforms:action>