禁止Update的多次刷新

public override void ItemUpdating(SPItemEventProperties properties)
        {
            this.DisableEventFiring();
            ConfigList cl = new ConfigList(properties.ListItem.Web.Site.RootWeb);
            cl.DoAction(properties, "Updated");
            this.EnableEventFiring();
            //properties.AfterProperties["State"].ToString() == properties.ListItem["State"].ToString()
        }