hi Kevat,
Since you are trying to retrieve data from previous page. I think there are more ways to do so.
For exmaple: - 

1. <div>Query String    </div>
2. <div>Session variables</div>
3. <div>Submit form using Hidden field.
   </div>

There are several examples you can search on google.
Suppose you want to pass the INTEGER (state_index) variable from Page1 to Page2 on button click event using QueryString.
                    
                   protected void Button1_Click(object sender, EventArgs e)
                   {
                        Response.Redirect("Page2.aspx?id=" + state_index); // QueryString Added to URL
                   }
                
                 To Read the value of "id" in Page2, you should use the below code in the

                  Page2_Load ()
                 {     
                  int qstr = (Int) Request.QueryString["id"];    //Now qstr will hold the data from the querystring.
                 }

Suppose you want to pass the state_index variable from Page1 to Page2 on button click event using Session. 
So, store a value inside a session variable as follows.
            
                protected void Button1_Click(object sender, EventArgs e)
                {
                         Session["Index"] = state_index;
                         Response.Redirect("Page2.aspx");
                }

Now, To retrieve the value from Page2 use the below code
                 Page2_Load ()
                 {     
                       int i  = (Int) session["Index"];
                 }

  Hope this will help you.
Thanks Regards
Dilipv