private static void OnSelectedEntityChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            IfcMetaDataControl ctrl = d as IfcMetaDataControl;

            if (ctrl != null && e.NewValue != null && e.NewValue is IPersistIfcEntity)
            {
                ctrl.DataRebind((IPersistIfcEntity)e.NewValue);
            }

            //ctrl.SetUpLinks();
        }
        private static void OnModelChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            IfcMetaDataControl ctrl = d as IfcMetaDataControl;

            if (ctrl != null)
            {
                if (e.NewValue == null)
                {
                    ctrl.Clear();
                }
                ctrl.DataRebind(null);
            }
        }