private void BindBillServices()
    {
        BillsServices bs    = new BillsServices();
        DataTable     table = bs.SelectAll();

        drpBillServices.DataSource     = table;
        drpBillServices.DataTextField  = "Name";
        drpBillServices.DataValueField = "BillsServices_ID";
        drpBillServices.DataBind();
        drpBillServices.Items.Insert(0, new ListItem("Select an Bills & Service....", "-1"));
    }
 private void GetBillServices(ref DataTable billsServicesTbl)
 {
     if (Session["BillServiceTable"] == null)
     {
         BillsServices bs = new BillsServices();
         billsServicesTbl = bs.SelectAll();
         Session.Add("BillServiceTable", billsServicesTbl);
     }
     else
     {
         billsServicesTbl = (DataTable)Session["BillServiceTable"];
     }
 }