Last modified on 10 September 2009, at 08:19

XForms/Spreadsheet-like Updating

Updating the ModelEdit

Many developers of traditional JavaScript-based forms are not accustomed to variables automatically updating for them. With XForms, you can easily create a complex system where XForms automatically figures out what cells to update. This is similar to using a spreadsheet. A dependency graph is automatically created for you and the appropriate cells are automatically updated if an input they depend upon changes.

Here is an example program that demonstrates this.

Screen ImageEdit

Here is a screen capture of the application:

XForms-spreadsheet-update.jpg

Note that top grid is actually just unlabeled input cells. Below that is a sample output inside a table. You should be able to change any of the input cells, enter a tab, and see the output and the footer calculations change.

Link to Working XForms ApplicationEdit

Spreadsheet-like Updating

Sample ProgramEdit

<html xmlns="http://www.w3.org/1999/xhtml" xmlns:xf="http://www.w3.org/2002/xforms" xmlns:ev="http://www.w3.org/2001/xml-events" xmlns:xs="http://www.w3.org/2001/XMLSchema">
   <head>
      <title>XForms Spreadsheat like Update</title>
      <style type="text/css">
    table {
       font-family: Arial, Helvetica, sans-serif;
        border-collapse: collapse;
      }
 
    th {
        color: white;
        background-color: black;
      }
 
    .output tr td {
       border: solid black 1px;
       padding: 2px;
       text-align: center;
    }
    </style>
      <xf:model>
         <xf:instance>
            <Spreadsheet xmlns="">
               <Row>
                  <A>10</A>
                  <B>20</B>
                  <C>30</C>
               </Row>
               <Row>
                  <A>40</A>
                  <B>50</B>
                  <C>60</C>
               </Row>
               <Row>
                  <A>70</A>
                  <B>80</B>
                  <C>90</C>
               </Row>
               <Results>
                  <sum/>
                  <avg/>
                  <min/>
               </Results>
            </Spreadsheet>
         </xf:instance>
         <xf:bind nodeset="/Spreadsheet/Results/sum" calculate="sum(/Spreadsheet/Row/A)" type="xs:decimal" />
         <xf:bind nodeset="/Spreadsheet/Results/avg" calculate="avg(/Spreadsheet/Row/B)" type="xs:decimal" />
         <xf:bind nodeset="/Spreadsheet/Results/min" calculate="min(/Spreadsheet/Row/C)" type="xs:decimal" />
      </xf:model>
   </head>
   <body>
      <xf:group ref="/Spreadsheet">
         <xf:input ref="Row[1]/A">
            <xf:label></xf:label>
         </xf:input>
         <xf:input ref="Row[1]/B">
            <xf:label></xf:label>
         </xf:input>
         <xf:input ref="Row[1]/C">
            <xf:label></xf:label>
         </xf:input>
         <br/>
         <xf:input ref="Row[2]/A">
            <xf:label></xf:label>
         </xf:input>
         <xf:input ref="Row[2]/B">
            <xf:label></xf:label>
         </xf:input>
         <xf:input ref="Row[2]/C">
            <xf:label></xf:label>
         </xf:input>
         <br/>
         <xf:input ref="Row[3]/A">
            <xf:label></xf:label>
         </xf:input>
         <xf:input ref="Row[3]/B">
            <xf:label></xf:label>
         </xf:input>
         <xf:input ref="Row[3]/C">
            <xf:label></xf:label>
         </xf:input>
         <table class="output">
            <thead>
               <tr>
                  <th>#</th>
                  <th>A</th>
                  <th>B</th>
                  <th>C</th>
               </tr>
            </thead>
            <tbody>
               <tr>
                  <td>
                     <xf:output value="1" />
                  </td>
                  <td>
                     <xf:output ref="Row[1]/A" />
                  </td>
                  <td>
                     <xf:output ref="Row[1]/B" />
                  </td>
                  <td>
                     <xf:output ref="Row[1]/C" />
                  </td>
               </tr>
               <tr>
                  <td>
                     <xf:output value="2" />
                  </td>
                  <td>
                     <xf:output ref="Row[2]/A" />
                  </td>
                  <td>
                     <xf:output ref="Row[2]/B" />
                  </td>
                  <td>
                     <xf:output ref="Row[2]/C" />
                  </td>
               </tr>
               <tr>
                  <td>
                     <xf:output value="3" />
                  </td>
                  <td>
                     <xf:output ref="Row[3]/A" />
                  </td>
                  <td>
                     <xf:output ref="Row[3]/B" />
                  </td>
                  <td>
                     <xf:output ref="Row[3]/C" />
                  </td>
               </tr>
               <tr>
                  <td />
                  <td>Sum=<xf:output ref="Results/sum" />
                  </td>
                  <td>Avg=<xf:output ref="Results/avg" />
                  </td>
                  <td>Min=<xf:output ref="Results/min" />
                  </td>
               </tr>
            </tbody>
         </table>
      </xf:group>
   </body>
</html>

DiscussionEdit

Due to limitations with some of the XForms implementations this example does not use the "repeat" command but just addresses each cell directly by its address.

Suggested ImprovementsEdit

This example could be a lot simpler if we used the repeat-nodeset statement in a table. This currently does not work with input cells using FormFaces.

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