Problem regarding the cart page of shopping website.

<asp:GridView ID="GridView2" runat="server" AutoGenerateColumns="False"
    DataKeyNames="Id" EmptyDataText="There are no data records to display."
         DataSourceID="ObjectDataSource1" >
    <Columns>
        <asp:BoundField DataField="Id" HeaderText="Id" ReadOnly="True"
            SortExpression="Id" />
        <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="name" />
        <asp:TemplateField HeaderText="pic">
            <EditItemTemplate>
                <asp:TextBox ID="TextBox2" runat="server" Text='<%# Eval("ImageUrl") %>'></asp:TextBox>
            </EditItemTemplate>
            <ItemTemplate>
                <asp:Image ID="Image1" runat="server" Height="63px"
                    ImageUrl='<%# Eval("ImageUrl") %>' Width="75px" />
            </ItemTemplate>
        </asp:TemplateField>
        <asp:BoundField DataField="Price" HeaderText="Price" SortExpression="Price" />

        <asp:TemplateField HeaderText="Item">
            <EditItemTemplate>
                <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
            </EditItemTemplate>
            <ItemTemplate>
                <asp:TextBox ID="TextBoxCount" runat="server" Height="19px"
                    Text='<%#Bind ("Item") %>' Width="35px"></asp:TextBox>
            </ItemTemplate>
        </asp:TemplateField>
        <asp:BoundField DataField="total" HeaderText="totalprice" />
        <asp:HyperLinkField DataNavigateUrlFields="Id"
            DataNavigateUrlFormatString="?DelID={0}" HeaderText="delete"
            Text="delete" />

        </Columns>
</asp:GridView>
<asp:ObjectDataSource ID="ObjectDataSource1" runat="server" SelectMethod="GetDetail"
         TypeName="BusinessLogic.ProductsBL">
    <SelectParameters>
        <asp:QueryStringParameter Name="Id" QueryStringField="ProductId" Type="Int32" />
    </SelectParameters>
     </asp:ObjectDataSource>
<asp:Button ID="Button1" runat="server" Text="Change" onclick="Button1_Click" />
<asp:Button ID="save" runat="server" Text="Save To Database" onclick="save_Click" />

public partial class Default2 : S
ystem.Web.UI.Page
{
    DataTable Basket_DataTable = null;
    protected void Page_Load(object sender, EventArgs e)
    {
        if (Session["basket"] != null)
        {
            Basket_DataTable = (DataTable)Session["basket"];
        }
        else
        {
            Basket_DataTable = new DataTable();
            Basket_DataTable.Columns.Add("Id");
            Basket_DataTable.Columns.Add("Name");
            Basket_DataTable.Columns.Add("ImageUrl");
            Basket_DataTable.Columns.Add("Price");
            Basket_DataTable.Columns.Add("Item");
            Basket_DataTable.Columns.Add("total");
        }

        if (Request["DelId"] != null)
        {
            for (int i = 0; i < Basket_DataTable.Rows.Count; i++)
            {
                if (Basket_DataTable.Rows[i][0].ToString() == Request["DelId"].ToString())
                    Basket_DataTable.Rows.Remove(Basket_DataTable.Rows[i]);
            }
        }
        if (Request["Id"] != null)
        {
            bool Found = false;
            for (int i = 0; i < Basket_DataTable.Rows.Count; i++)
            {
                if (Basket_DataTable.Rows[i][0].ToString() == Request["Id"].ToString())
                    Found = true;

            }
            if (Found == false)
            {
                DataAccess.TestDA data = new DataAccess.TestDA();
                string sql = "Select * from Products where Id=" + Request["Id"];
                DataTable ret = data.exe_select(sql);
                if (ret != null && ret.Rows.Count == 1)
                {
                    Basket_DataTable.Rows.Add(new object[]{Request["Id"],ret.Rows[0]["Name"].ToString(),
                      ret.Rows[0]["Price"].ToString(),ret.Rows[0]["ImageUrl"].ToString()
                      ,"1",ret.Rows[0]["Price"].ToString()});


                }

            }
        }
        if (IsPostBack == false)
        {
            //GridView2.DataSource = Basket_DataTable;
            GridView2.DataBind();
        }

        Session["basket"] = Basket_DataTable;
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        try
        {
            for (int i = 0; i < GridView2.Rows.Count; i++)
            {
                TextBox Tb = (TextBox)GridView2.Rows[i].FindControl("TextBoxCount");
                Basket_DataTable.Rows[i]["Item"] = Tb.Text;
                Basket_DataTable.Rows[i]["total"] = Convert.ToInt32(Tb.Text) * Convert.ToInt32(Basket_DataTable.Rows[i]["Price"]);
            }
        }
        catch
        {

        }
       // Response.Redirect("TestShopcart.aspx");
    }
    protected void save_Click(object sender, EventArgs e)
    {
        DataAccess.TestDA data = new DataAccess.TestDA();
        for (int i = 0; i < GridView2.Rows.Count; i++)
        {
            String Id = GridView2.Rows[i].Cells[0].Text.ToString();
            TextBox Tb = (TextBox)GridView2.Rows[i].FindControl("TextBoxCount");
            string sql = "Insert into Mycart(ProductsId) values({0})";
            sql = string.Format(sql, Tb.Text, Id);
            data.exe_cmd(sql);
        }


    }
}