title: gridview merge column headers
body: <p>I have a gridview and I want to merge the headers of column (n) and (n+1) into one so that the output will use colspan to show a single header for columns n and n+1. I've seen several ways to do it by googling for this technique but all seem to be rather cumbersome and verbose. </p>
  
  <p>I was wondering if someone had come across an elegant a short solution.</p>