title: How to get a total of column value
body: <p>Using flexgrid.</p>
  
  <p>flexgrid row</p>
  
  <pre><code>id value
  
  001 200
  003 400
  002 600
  ...
  </code></pre>
  
  <p>I want to sum the value column, sum(value) in flex grid, </p>
  
  <p>Flexgrid rows are populating from the table, at last right side i want to show the
  total of value column in flex grid itself.  How to do this.</p>
  
  <p>Expected Output</p>
  
  <pre><code>id value
  
  001 200
  003 400
  002 600
  ........
  
  Total 1200 ' I want to show the total in flex grid itself...
  </code></pre>