How to store selected checkboxes of datagrid in sessions?

Question

hi!
i am using datagrid to display data, in my datagrid i take checkboxes, and i take paging also and my problem is when i check checkboxes and i go to next page of datagrid this selected checkbox of first page checkboxes are unchecked.
  my aim is user select the checkboxes and he goes to next page still previous checkboxes also checked until user unchecks the checkboxes.
  using sessions how to store selected checkboxes of datagrid in sessions. please give a solutions and give a sample code of todo this.
Thanks.