Data Controls :: Bind Data List With Two Querystring

I have 2 page 1-index.aspx  2-Search.aspx

in index.aspx page I have Textbox =txtsearch  and Button =searchbutton 

in Textbox users enter text and when they click on serachbutton it goes to search.aspx page and according to txtsearch's text it bind datalist=>DDLStore  that I define in search.aspx page

below is searchbutton code in index.aspx page

protected void searchbutton_click(object sender, ImageClickEventArgs e) {
Response.Redirect("search.aspx?data=" + Server.UrlEncode(txtsearch.Text));
}

And this is method that I bind datalist => DDLStore in search.aspx page

private void GetCustomersPageWiseStore(int pageIndex) {
using (SqlCommand cmd = new SqlCommand("GCPSearch", _cn)) {
string search = Server.UrlDecode(Request.QueryString["data"]);

[code]....

this querystring come from index.aspx page but I don't know how I can define something like  that for search.aspx page...I mean I want if users enter text in txtsearch in index.aspx  or they enter text in txtStore in search.aspx  in both position it bind DDLStore..