dfAddRecord.CurrentItem = <моя_новая_запись>

    private void AddItem_ItemClick(object sender, ItemClickEventArgs e)
        {
тут переходим на Page
        }

 <dxb:BarButtonItem Name="bOpen" Content="Открыть" 
                               Glyph="/TSU_Plan;component/Images/openfolder_16x16.png"
                               LargeGlyph="/TSU_Plan;component/Images/openfolder_26x26.png"
                               Hint="Открыть план" ItemClick="bOpen_ItemClick">
 </dxb:BarButtonItem>

   public partial class MainPage : UserControl
    {
        Binding binding;

        public MainPage()
        {
            InitializeComponent();
        }
        public enum Pages
        {
            Page_add
        }
        private Dictionary<Pages, UserControl> pageCache = new Dictionary<Pages, UserControl>();

        public void Navigate(Pages newPage)
        {
            App currentApp = (App)Application.Current;
            if (!pageCache.ContainsKey(newPage))
            {
                Type type = currentApp.GetType();
                Assembly assembly = type.Assembly;
                pageCache[newPage] = (UserControl)assembly.CreateInstance(type.Namespace + "." + newPage.ToString());
                pageCache[newPage].SetBinding(Page.DataContextProperty, binding);
            }
            viewBox.Child = pageCache[newPage];
        }


        private void bOpen_ItemClick(object sender, DevExpress.Xpf.Bars.ItemClickEventArgs e)
        {
            Navigate(Pages.Page_add);
        }

 <Border  Name="viewBox" />