WPF MVVM DataGrid is row has has validation error

the anwser here https://social.msdn.microsoft.com/Forums/vstudio/en-US/18ea596e-ae96-481c-a928-a51c23fbf912/datagrid-blankcell-validationrules-and-mvvm-problem?forum=wpf#26dadcb6-9d30-4f70-b556-89fdda8d960d helped me to apply validation rules to a row in datagrid

i had this class to get me changed items in the datagrid 

public class DataGridSelectedItemsBlendBehavior : Behavior<DataGrid>
    {
        public static readonly DependencyProperty HasValidationErrorProperty =
            DependencyProperty.Register("HasValidationError", typeof(bool),
            typeof(DataGridSelectedItemsBlendBehavior),
            new FrameworkPropertyMetadata(null)
            {
                BindsTwoWayByDefault = true
            });

        public static readonly DependencyProperty SelectedItemProperty =
            DependencyProperty.Register("SelectedItems", typeof(IList),
            typeof(DataGridSelectedItemsBlendBehavior),
            new FrameworkPropertyMetadata(null)
            {
                BindsTwoWayByDefault = true
            });

        public static readonly DependencyProperty ChangedItemProperty =
            DependencyProperty.Register("ChangedItems", typeof(IList),
            typeof(DataGridSelectedItemsBlendBehavior),
            new FrameworkPropertyMetadata(null)
            {
                BindsTwoWayByDefault = true
            });

        public bool HasValidationError
        {
            get
            {
                return (bool)GetValue(HasValidationErrorProperty);
            }
            set
            {
                SetValue(HasValidationErrorProperty, value);
            }
        }

        public IList SelectedItems
        {
            get
            {
                return (IList)GetValue(SelectedItemProperty);
            }
            set
            {
                SetValue(SelectedItemProperty, value);
            }
        }

        public IList ChangedItems
        {
            get
            {
                return (IList)GetValue(ChangedItemProperty);
            }
            set
            {
                SetValue(ChangedItemProperty, value);
            }
        }

        protected override void OnAttached()
        {
            base.OnAttached();
            this.AssociatedObject.SelectionChanged += OnSelectionChanged;
            this.AssociatedObject.RowEditEnding += OnRowEditEnding;
            this.AssociatedObject.Loaded += AssociatedObject_Loaded;
        }

        void AssociatedObject_Loaded(object sender, RoutedEventArgs e)
        {
            if (this.SelectedItems != null)
            {
                var selectedItems = this.SelectedItems;
                foreach (var obj in selectedItems)
                {
                    var rowContainer = this.AssociatedObject.ItemContainerGenerator.ContainerFromItem(obj) as DataGridRow;
                    if (rowContainer != null)
                    {
                        rowContainer.IsSelected = true;
                    }
                }
            }
        }

        protected override void OnDetaching()
        {
            base.OnDetaching();
            if (this.AssociatedObject != null)
            {
                this.AssociatedObject.SelectionChanged -= OnSelectionChanged;
                this.AssociatedObject.RowEditEnding -= OnRowEditEnding;
                this.AssociatedObject.Loaded -= AssociatedObject_Loaded;
            }
        }

        /// <summary>
        /// Add/remove row to selected items collection based on user interaction with the datagrid with shift or ctrl buttons
        /// </summary>
        private void OnSelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            if (e.AddedItems != null && e.AddedItems.Count > 0 && this.SelectedItems != null)
            {
                foreach (object obj in e.AddedItems)
                {
                    if (obj.ToString() == "{NewItemPlaceholder}")
                    {
                        continue;
                    }
                    this.SelectedItems.Add(obj);
                }
            }

            if (e.RemovedItems != null && e.RemovedItems.Count > 0 && this.SelectedItems != null)
            {
                foreach (object obj in e.RemovedItems)
                {
                    this.SelectedItems.Remove(obj);
                }
            }
        }

        public static bool IsValid(DependencyObject obj)
        {
            return obj == null
                ? false
                : !Validation.GetHasError(obj) && LogicalTreeHelper.GetChildren(obj).OfType<DependencyObject>().All(IsValid);
        }

        /// <summary>
        /// add the commited items in the datagrid to changeditems collection
        /// </summary>
        private void OnRowEditEnding(object sender, DataGridRowEditEndingEventArgs e)
        {
            if (e.EditAction == DataGridEditAction.Commit)
            {
                if (!IsValid(e.Row as DependencyObject))
                {
                    HasValidationError = true;
                    return;
                }
                var item = ChangedItems.Cast<object>().SingleOrDefault(i => i != null);
                if (item == null)
                {
                    this.ChangedItems.Add(e.Row.Item);
                }
                else
                {
                    item = e.Row.Item;
                }
                HasValidationError = false;
            }
        }
    }

i want to stop adding the row to the changed items if it has a validation error but the "e.row.item" for "DataGridRowEditEndingEventArgs" only gets the data when i first start editing for example if i added a new row the e.row.item column "Name" will be empty even if i added data to it until i hit enter and start editing again is there is a way to get a around it? or a better way to know if a row has a validation error ?