在GridView做加減並更新

 protected void gv_DataBound(object sender, EventArgs e)
    {
        for (int i = 0; i < gv.Rows.Count; i++)
        {
            Label aa = (Label)gv.Rows[i].Cells[6].FindControl("Label3");
            
            if (aa != null)
            {
                if (aa.Text.Trim().StartsWith("-")) aa.Text = "0";
                int number;
                string hu = aa.Text.Trim();
                int.TryParse(hu, out number);
                int num2 = int.Parse(DropDownList1.SelectedValue);
                int num3 = number * num2;
                gv.Rows[i].Cells[7].Text = num3.ToString();
            }
            
        }


    }

    protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        SqlDataSource ses = new SqlDataSource();
        ses.ConnectionString = System.Web.Configuration.WebConfigurationManager.ConnectionStrings["immis"].ConnectionString;
        ses.UpdateCommand = "update hi set total=@total where id=101";
        ses.UpdateParameters.Add(new Parameter("total", TypeCode.String));
        ses.UpdateParameters["total"].DefaultValue = DropDownList1.SelectedValue.ToString();
        ses.Update();

    }