title: DataGrid - Displaying Running Total From Top of Grid Through Current Row
body: <p>How would I display a running total for a particular column of each record that is displayed in a DataGrid? I'd like to keep the computation logic in the view model.</p>
  
  <p>Desired Output:</p>
  
  <pre>
  Value      | Running Total
  25           25
  10           35
  -2           33
  </pre>
  
  <p>Thank you,<br>
  Ben</p>
  
  <p><strong>Edit:</strong> Keep in mind that when a user-triggered DataGrid sort occurs, the running totals must be recalculated because the record display order has changed.</p>
  
  <p>I'd really like to put the logic for this in the view model, not in WPF code (e.g. not using an IValueConverter).</p>