The Control Element

This element embeds an XForm in the current form.

Common Attributes: Control Common

Special attributes:

resource
Required URL of a resource containing an XForm. This form will be embedded within the current form.
ref (also bind)
Optional single node binding that indicates the target node to receive submissions using the 'xforms-return' method in the embedded form. It may be the same node as that used in the 'initial' attribute below. If absent, no values are expected from the embedded form; if the embedded form does nevertheless try to return values, the submission will fail with 'xforms-return'.
initial
Optional single node expression. The value of this node is used to initialise the textually first instance in the embedded form, in the same way as a <submit replace="instance"/> would work. If absent, no values are passed to the embedded form. [Should this be a nodeset?]

Content: EMPTY

The resource attribute is evaluated. If the resource is not found, or it is not an XForm, an xforms-link-error is dispatched to the control element, and the control element has no effect.

The resource is embedded in the current form at the current textual position.

The initial attribute is evaluated and the node and all its descendants are selected. [Do we select for relevance?]

The textually first instance in the embedded form is replaced by the selected node and descendants, as if by a submission with replace="instance". [if there is no such instance...].

The embedded form is initialised in the normal way.

If at any time the embedded form processes a submission with method="xforms-return", the submission values are used to replace the content of the binding identified by the ref or bind attribute of the control element. The node is replaced in the same way as a submission with replace="instance" targetref="...".

Examples

An embedded control with no initial values, and no result:

<control resource="today.xhtml" label="Today's date:"/>

---today.xhtml:

<output value="now()"/>

An embedded control with initial values and no result:

<instance>
   <data xmlns="">
      <before>
         <y>9</y><y>15</y><y>11</y><y>6</y><y>5</y><y>10</y><y>8</y>
      </before>
      <after>
         <y>8</y><y>3</y><y>12</y><y>14</y><y>9</y><y>16</y><y>14</y>
      </after>
   </data>
</instance>
 ...
<control resource="histogram.xhtml" initial="before" label="Before"/>
<control resource="histogram.xhtml" initial="after"  label="After"/>

An embedded control with a result but no initial values:

<instance>
   <data xmlns="">
      <testfile>test.xml</testfile>
   </data>
</instance>
<instance id="results"/>
 ...
<control ref="instance('results')" resource="{testfile}"/>

---In test.xml

<instance>
   <data xmlns="">
      <values>...</values>
      <results>
         <percent/>
         <success/>
         <failure/>
      </results>
   </data>
</instance>
 ...
<submission ref="results" method="xforms-return"/>

An embedded control with both initial values and result:

<instance id="values">
   <data xmlns="">
      <a>1</a>
      <b>2</b>
      <sum/>
   </data>
</instance>
 ...
<control ref="instance('values')" resource="add.xhtml" initial="instance('values')"/>
<output ref="sum"/>

---In add.xhtml:

<instance>
   <values xmlns=""/>
</instance>
<bind ref="sum" calculate="../a + ../b"/>
<submission method="xforms-return"/>

An embedded control with both initial values and result:

<instance>
   <locations xmlns="">
      <here x="3498234" y="8734503"/>
      <home x="" y=""/>
      <dest x="" y=""/>
   </locations>
</instance> ...

<control ref="home" resource="map.xf" initial="here" label="Please locate your home location"/>
<control ref="dest" resource="map.xf" initial="here" label="Please locate your destination"/>

A series of embedded controls with both initial values and results:

<instance> 
   <testsuite xmlns="">
      <testcase>
         <filename>boolean-from-string.xml</filename>
         <tests>
            <test res="" req="true">1</test>
            <test res="" req="false">0</test>
         </tests>
         <result/>
      </testcase>
      <testcase>
         ...
      </testcase>
   </testsuite>
</instance>

<repeat ref="testcase">
   <control resource="{filename}" initial="tests" ref="result"/>
</repeat>

---in the subform

<model>
   <instance>
      <tests xmlns=""/>
   </instance>
   <instance id="result">
      <result xmlns="">
         <percent/>
      </result>
   </instance>
   ...
   <submission ref="instance('result')" method="xforms-return"/>
</model>

Selecting a control to embed:

<select1 ref="game" label="select a game to play">
   <item label="minesweeper">minesweeper.xml</item>
   <item label="slider">slider.xml</item>
   <item label="noughts and crosses">xox.xml</item>
</select1>
<control resource="{game}"/>

The renew Element

This action causes the initial values of an embedded form to be re-initialised, possibly with new values.

Attributes: Common

Special attributes:

control
Required ID of a control element.

Examples

<instance id="start">
   <data xmlns="">
      <attempt>1</attempt>
      <score>0</score>
   </data>
</instance>
 ...
<control id="game" resource="game.xml" initial="instance('start')"/>
<trigger label="restart">
   <action ev:event="DOMActivate">
      <setvalue ref="attempt" value=". + 1"/>
      <setvalue ref="score" value="0"/>
      <renew control="game"/>
   </action>
</trigger>

The signal element

This action dispatches an event to or from an embedded control.

Attributes: Common

Special attributes:

name
Required string, the name of an event to be dispatched.
control
Optional ID of a control element.

[Note: No delay, targetid, bubbles or cancelable attributes.]

Content: property*

An event is created with its name set to the value of the name attribute.

If the signal element has any property child elements, the event context is updated with their values.

If the control attribute is present, that control element is identified, and the event is dispatched to the textually first model element of the form embedded by the control element, if any.

If the control attribute is absent, the event is dispatched to the control element that caused this form to be embedded. If the current form is not embedded in another, then the action has no effect.

The xforms-return Submission Method

With this method, the resource attribute of the submission element is ignored. If the submitting form has not been embedded in another, or the embedding form has not supplied a receiving binding for submission results, submission fails with return-error. Otherwise, the form data is returned to the embedding XForm, and is used to replace the node specified in the ref or bind attribute of the control element in that form, as if by a submission with replace="instance" targetref="...".