?using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public partial class Default3 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {

            GridView1.DataSource = Session["ShoppingCart"];
            DataBind();
        }
    }
    protected void GridView1_RowCommand1(object sender, GridViewCommandEventArgs e)
    {
        System.Data.DataTable Cart = new System.Data.DataTable();
        if (e.CommandName == "sel")
        {
            if (Session["ShoppingCart2"] == null)
            {
                Cart.Columns.Add("菜名稱", typeof(string));

                Cart.Columns.Add("單價", typeof(double));
                Cart.Columns.Add("數(shù)量", typeof(int));
                Cart.Columns.Add("折扣", typeof(double));
                Cart.Columns.Add("合計", typeof(double));

                Session["shoppingCart2"] = Cart;
            }

            Cart = (System.Data.DataTable)Session["ShoppingCart2"];
            int index = Convert.ToInt32(e.CommandArgument);
            GridViewRow row = GridView1.Rows[index];
            TextBox tt = (System.Web.UI.WebControls.TextBox)row.Cells[1].FindControl("TextBox1");

            string dgl = tt.Text;
          int dg = int.Parse(dgl);

            //if(dg<=1) dg=1;

            string mcText = row.Cells[1].Text;

            string djText = row.Cells[2].Text;
            double dj = double.Parse(djText);

            //double c=double.Parse(ss);
            System.Data.DataRow rr = Cart.NewRow();
            rr["菜名稱"] = mcText;
            rr["單價"] = djText;
            rr["數(shù)量"] = dg;
            int z = 1;
            rr["折扣"] = z;
            double hj = dj * dg * z;
            rr["合計"] = hj;
            Cart.Rows.Add(rr);
            Session["ShoppingCart2"] = Cart;

        }
        

    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        Response.Redirect("BookTable.aspx");
    }
    protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
    {

    }
}