Problem in Gridview when refresh page..

Question

i have applied edit,delete,update,insert operation  successfully,everything is work Correctly.

But when i refresh the page,last operation performed  again after refresh .

suppose  when i updated any record before refresh ,one insertion took place after refresh .

when i inserted record before refresh page.same record inserted again...i have no idea why has been this happening.

if anybody want to see my code,i will show..

Thanks in advance