Updating gridview rows using sqldatasource
like onrowupdating event after performing all operation i call display method at the end.
you also check this link please , by thw way ur link is not working. So, the View State with all of the data for your Grid View is loaded just after the Init event.
What you would have to do is implement a method that handles the Grid View. In this method you will have to retrieve the data from the row that is updating and use this data to update your database.
I'm not sure what you're stuck on so if you provide more information I can give you more help on the topic.
I'm not even sure you have a question at this point...