title: How to maintain the checkbox state in the header rows across the page?
body: <p>I know how to keep track of the checkbox in a datarow, but I got no idea on keep tracking the checkbox state in the header rows. </p>
  
  <p>For example, assume my gridview have 3 pages, after I check the checkbox in the header rows in 1st page, I click on 2nd or 3rd pages, and click back to my 1st page, my checkbox status in 1st page still remains checked. 
  What's the solution for it? Sample codes provided is appreciated.</p>