How to set the Grid row order based on the value from Gridview Row Databound event

Question

Hi,

 I am binding a gridview to view all tickets in wich all the data is read form table "tickets" but the updation date is read from other table i.e. "TicketReply"

While showing gridview i am assigning the updationdate read form other talbe(ticketreply) to the gridview

now i want the gridview rows should display order by (updation date)

i am wondering how to sort the rows order based on the value set from row_databound event of gridview