Add the Values to View State

hi friends i have a one doubt


that is
 in gridview checkboxes are there and id's are appended to that check boxes and i am using pagingconcept in grid view
if check two rows in first page and i check another two rows in 2nd page how can i get ids of the checkboxes first and second....

i am using using
int i=request.form("chkbox1");

if i get the first checked items when i navigate to another page of gridview those checked items will be losses....my reqirement is i can get all the checked id's of the gripaging....how can i....

please give me the code for this one.....