public OrderPage()
{
this.InitializeComponent();
this.navigationHelper = new NavigationHelper(this);
this.navigationHelper.LoadState += navigationHelper_LoadState;
this.navigationHelper.SaveState += navigationHelper_SaveState;
}
protected PageBase()
{
_navigationHelper = new NavigationHelper(this);
_navigationHelper.LoadState += NavigationHelperLoadState;
_navigationHelper.SaveState += NavigationHelperSaveState;
}