XForms/Table Column Total

Motivation

Frequently a form must display the total of a column. This can be accomplished using the bind function in the model.

Screen Image

Calculating the total of a column

Sample Program

<html
    xmlns="http://www.w3.org/1999/xhtml"
    xmlns:ev="http://www.w3.org/2001/xml-events"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema"
    xmlns:xf="http://www.w3.org/2002/xforms"
    >
   <head>
      <style type="text/css">
     @namespace xf url("http://www.w3.org/2002/xforms");

   * { font-family: Ariel, Helvetica, sans-serif }

   .table-header, .table-footer {
      display: table-row;
   }
   
   .column-header, .column-footer {
      display: table-cell;
      text-align: center;
      color: white;
      background-color: gray;
      font-weight: bold;
   }
   
   /* make the "Total:" in the table footer right align */
   .table-footer .item-description,
   .table-footer .item-amount {
      text-align: right;
   }
   
   .item-description {
      width: 300px;
   }
   
   .item-amount {
      width: 112px;
   }
   
   .item-description .xf-value {
      width: 300px;
      text-align: left
    }
   
   .item-amount .xf-value {
      width: 100px;
      text-align: right
    }

    </style>
      <title>Demonstration of table with column total</title>
      <xf:model id="my-model">
         <xf:instance id="my-data" src="my-data.xml" xmlns=""/>
         <xf:bind nodeset="/Data/Total" calculate="sum(../Item/Amount)"/>
         <xf:submission id="update-from-local-file" method="get" action="my-data.xml" 
              replace="instance" instance="my-crv"/>
         <xf:submission id="view-xml-instance" method="get" action="my-data.xml"/>
         <xf:submission id="save-to-local-file" method="put" action="my-data.xml"/>
      </xf:model>
   </head>
   <body>
      <div class="table-header">
         <div class="column-header item-description">Description</div>
         <div class="column-header item-amount">Value</div>
      </div>
      <xf:group ref="/Data">
         <!-- For each Person in the PersonList display the name and phone-->
         <xf:repeat nodeset="Item" id="repeatItem">
            <xf:input id="description-input" ref="Description" class="item-description"/>
            <xf:input ref="Amount" class="item-amount"/>
            <br />
         </xf:repeat>
         <div class="table-footer">
            <div class="column-footer item-description">Total:</div>
            <div class="column-footer item-amount">
               <xf:output ref="/Data/Total" />
            </div>
         </div>
         <xf:trigger id="insertbutton">
            <xf:label>Add Item</xf:label>
            <xf:action ev:event="DOMActivate">
               <xf:insert nodeset="Item[last()]" position="after" at="last()"/>
               <xf:setvalue ref="Item[last()]/Description" value="''"/>
               <xf:setvalue ref="Item[last()]/Amount" value="0"/>
               <!-- put the cursor in the name field -->
               <xf:setfocus control="description-input"/>
            </xf:action>
         </xf:trigger>
         <xf:trigger id="delete">
            <xf:label>Delete Item</xf:label>
            <xf:delete nodeset="Item[index('repeatItem')]"
                at="index('repeatItem')" ev:event="DOMActivate"/>
         </xf:trigger>
         <br />
         <xf:submit submission="update-from-local-file">
            <xf:label>Reload</xf:label>
         </xf:submit>
         <xf:submit submission="save-to-local-file">
            <xf:label>Save</xf:label>
         </xf:submit>
         <xf:submit submission="view-xml-instance">
            <xf:label>View XML Instance</xf:label>
         </xf:submit>
      </xf:group>
   </body>
</html>

Sample my-data.xml instance file

<?xml version="1.0" encoding="UTF-8"?>
<Data>
   <Item>
      <Description>Furniture</Description>
      <Amount>1000</Amount>
   </Item>
   <Item>
      <Description>Dock</Description>
      <Amount>2000</Amount>
   </Item>
   <Item>
      <Description>Boat</Description>
      <Amount>3000</Amount>
   </Item>
   <Item>
      <Description>Lawn equipment</Description>
      <Amount>4000</Amount>
   </Item>
   <Item>
      <Description>Hot tub</Description>
      <Amount>5000</Amount>
   </Item>
   <Total>15000</Total>
</Data>

Discussion

This example uses div blocks for the table header and footer. The total will be updated each time the user tabs out of a field. New items are always added to the end but you can delete an existing item just by selecting it and pressing the "Delete item" button.

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