public void DisplayDataTables()
{
ServerFactory serverFactory = (ServerFactory)Session[Constants.ServersFactory];
serverGrid.DataSource = serverFactory.GetServerDataTable();
serverGrid.DataBind();
MenuItemFactory menuFactory = (MenuItemFactory)Session[Constants.MenuItemsFactory];
menuGrid.DataSource = menuFactory.GetMenuDataTable();
menuGrid.DataBind();
OrderFactory orderFactory = (OrderFactory)Session[Constants.OrderFactory];
orderGrid.DataSource = orderFactory.GetOrderDataTable();
orderGrid.DataBind();
orderItemGrid.DataSource = orderFactory.GetOrderItemDataTable();
orderItemGrid.DataBind();
}