protected void btnDelete_Click(object sender, EventArgs e)
 {
     if (Session["ProductPKID"].ToString() != "" && long.TryParse(Session["ProductPKID"].ToString(), out _PKID))
     {
         _PKID = long.Parse(Session["ProductPKID"].ToString());
         _product = new ProductClass(_PKID);
         _product.deleteRecord(_PKID);
         Session["ProductPKID"] = "";
     }
     fillGridView();
 }
 protected void Page_Load(object sender, EventArgs e)
 {
     if (Session["ProductPKID"].ToString() != "" && long.TryParse(Session["ProductPKID"].ToString(), out _PKID))
     {
         _PKID = long.Parse(Session["ProductPKID"].ToString());
         _product = new ProductClass(_PKID);
         if (!Page.IsPostBack)
         {
             displayRecord();
         }
     }
     else
     {
         _product = new ProductClass();
     }
 }