pass value between asp pages from data grid view

p:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
    <asp:GridView ID="GridView1" runat="server" BackColor="White"
                        BorderColor="#DEDFDE" BorderStyle="None"
    BorderWidth="1px" CellPadding="4"
                        ForeColor="Black" GridLines="Vertical" onrowcommand="GridView1_RowCommand"
                        Width="595px" AllowPaging="True"
                        onpageindexchanging="GridView1_PageIndexChanging"
    PageSize="6">
                        <PagerSettings FirstPageText="First" LastPageText="Last"
                            Mode="NextPreviousFirstLast" NextPageText="Next" PreviousPageText="Prev" />
                        <RowStyle BackColor="#F7F7DE" />
                        <Columns>
                            <asp:ButtonField ButtonType="Button" CommandName="Edit" HeaderText="Edit"
                                ShowHeader="True" Text="Edit" />
                        </Columns>
                        <FooterStyle BackColor="#CCCC99" />
                        <PagerStyle BackColor="#F7F7DE" ForeColor="Black" HorizontalAlign="Right" />
                        <SelectedRowStyle BackColor="#CE5D5A" Font-Bold="True" ForeColor="White" />
                        <HeaderStyle BackColor="#6B696B" Font-Bold="True" ForeColor="White" />
                        <AlternatingRowStyle BackColor="White" />
                    </asp:GridView>





page.cs code


 protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)
    {
        if (e.CommandName == "Edit")
        {
            int x = Convert.ToInt32(e.CommandArgument.ToString());
            Class1.index = x;
            Session["index"] = x;
            Response.Redirect("Update.aspx?ID=" +x);
        }
    }
    protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
    {
        GridView1.PageIndex = e.NewPageIndex;
        GridView1.DataBind();

    }