How to reset Gridview Sort on buttonclick event

Hello,

I have a gridview and I used sqldatasource to bind data with gridview 

Sorting is working correctly 

But on first button click event  If i sort column Name by desc

and on second button click event the sort order for column name id desc only 

Can you please tell me how to reset column sort as per sql query on every button click event ? 

Thank you

Sandy