want to print all gridview row in asp.net C#

Hi all,
lets say , there are 20 rows in my gridview. I set Pagesize=5  and AllowPaging=true.
So there are 5 rows in one page in my girdview.
When I print my gridview in PDF format, only 5 rows appear coz of paging event.
How can I make output all of my gridview row in printing as PDF format.
Thanks in advance .