problem in getting all rows of gridview when paging is true

Hi All,

i have a gridview with 1000 of rows and textbox, and checkbox , so i did allowpaging =true. now i want to traverse all the rows and get value of checked textbox.
but if i do somethn like ths foreach (GridViewRow gvrow in gridview1.Rows) it only traverse current page.
so i have done like this:
gridview1.AllowPaging = false;
gridview1.databind()
/// do stuff
gridview1.AllowPaging = true;
gridview1.databind().

but the problem is tht i cannot retain my textbox value.
could somebody help me, stuck badly