title: How to programmatically update datagrid columns headerText
body: <p>I have a Datagrid that is being populated by an ArrayCollection (rows) of Arrays (columns).  I need to update the headerText of each column based on a List that will correspond with the total number of items within each array in the arraycollection.  </p>
  
  <p>What is the best way of doing this?  </p>
  
  <p>I know that I can set a listener in the List and update the headerText using (matrixDatagrid.columns[i] as DataGridColumn).headerText but I am looking for a cleaner solution. </p>
  
  <p>Is there a way to do this using an itemRenderer in the Datagrid?</p>