Saving user's response for several pages

Hi guys!
I have a default.aspx page, it contains a checkboxlist and button (Button1). There are other items too but not significant for this question.
The user selects an item in the checkbox list.  Based on which item is selected, in my button click code, I take the user to another page (Page2, for example). In that page I have TextBoxes, where user fills some numeric values. On this page (Page2) I have another button (Button2). In the Button2 Click code, I want to use logic, where I need to know what was checked in my checkboxlist in previous page. How can I do that.  I get the error
Error 17 The name 'CheckBoxList1' does not exist in the current context 
On default page Button click I have like this..
foreach (ListItem item in CheckBoxList1.Items)
        {
            if (item.Selected)
& ...