.CS

protected void Page_Load(object sender, EventArgs e)
        {
            //Stabilisco la connessione al server
            string conn = "Server=PC1319; Database=kitkits; User Id=sa; Password=1mp0ss1b1l3;";
            SqlConnection con = new SqlConnection(conn);

            ////Richiamo la stored procedure
            //SqlCommand cmd = new SqlCommand("Cerca_Acquisti_Cliente", con);
            //cmd.CommandType = CommandType.StoredProcedure;
            //cmd.Parameters.Add(new SqlParameter("@nome", "Tiberio"));
            //cmd.Parameters.Add(new SqlParameter("@cognome", "Tonetti"));
            //DataSet ds = new DataSet();
            //SqlDataAdapter da = new SqlDataAdapter(cmd);
            //da.Fill(ds, "Kit");
            //GridView1.DataSource = ds.Tables["Kit"].DefaultView;
            //GridView1.DataBind();

            ////Richiamo la stored procedure
            //cmd = new SqlCommand("Cerca_per_prezzo", con);
            //cmd.CommandType = CommandType.StoredProcedure;
            //cmd.Parameters.Add(new SqlParameter("@prezzo", 150));
            //ds = new DataSet();
            //da = new SqlDataAdapter(cmd);
            //da.Fill(ds, "Kit");
            //GridView2.DataSource = ds.Tables["Kit"].DefaultView;
            //GridView2.DataBind();

            if (Session["id"] == "")
            {
            }
            else
            {
                foreach (string i in (List<string>)Session["Carrello"])

                    ListBox1.Items.Add(i);

                //    string conn = "Server=PC1319; Database=kitkits; User Id=sa; Password=1mp0ss1b1l3;";
                //SqlConnection con = new SqlConnection(conn);
                //DataSet dset = new DataSet();


                //    SqlCommand cmd = new SqlCommand("SELECT * FROM Acquisti JOIN Cliente ON Cliente.Id=IdCliente WHERE username='"+Session["id"]+"'", con);
                //    SqlDataAdapter da = new SqlDataAdapter(cmd);
                //    da.Fill(dset, "Carrello");

                //    GridView1.DataSource = ((DataSet)Application["ds"]).Tables["Acquisti"].DefaultView;
                //    GridView1.DataBind();


                //Richiamo la stored procedure
                SqlCommand cmd = new SqlCommand("Cerca_Acquisti_Cliente", con);
                cmd.CommandType = CommandType.StoredProcedure;
                cmd.Parameters.Add(new SqlParameter("@username", Session["id"].ToString()));
                DataSet ds = new DataSet();
                SqlDataAdapter da = new SqlDataAdapter(cmd);
                da.Fill(ds, "Acquisti");
                GridView1.DataSource = ds.Tables["Acquisti"].DefaultView;
                GridView1.DataBind();
            }
.ASPX
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder2" runat="server">
    <h2 class="auto-style5"><strong>Cart</strong></h2>
    <p id="idcar">
        <asp:ListBox ID="ListBox1" runat="server"></asp:ListBox>
    </p>
<p>
        Acquisti recenti</p>
<p>
        <asp:GridView ID="GridView1" runat="server">
        </asp:GridView>
    </p>
</asp:Content>