XamDataGrid - Setting keyboard focus back to Add row

MyViewWithGrid.cs

//Add a PreviewKeyDown event handler to the data grid and call the HandleFocus method.
private void DataGrid_PreviewKeyDown(object sender, System.Windows.Input.KeyEventArgs e)
{
    XamDataGridFocusHelper.HandleFocus(sender, e);
}

XamDataGridFocusHelper.cs

using System;
using System.Linq;
using System.Windows;
using System.Windows.Input;
using System.Windows.Threading;
using Infragistics.Windows.DataPresenter;

namespace Chris.Blog
{
    public static class XamDataGridFocusHelper
    {
        public static void HandleFocus(XamDataGrid grid, Key keyPressed)
        {
            if ((keyPressed == Key.Tab && !Keyboard.IsKeyDown(Key.LeftShift) && !Keyboard.IsKeyDown(Key.RightShift) && IsLastFieldFocused(grid)))
            {
                grid.Dispatcher.BeginInvoke(new Action(() =>
                    CellValuePresenter.FromCell(grid.RecordManager.CurrentAddRecord.Cells.First(c => c.Field.AllowEditResolved)).Editor.StartEditMode()), 
                    DispatcherPriority.Background, null);
            }
        }

        public static void HandleFocus(object grid, System.Windows.Input.KeyEventArgs e)
        {
            HandleFocus((XamDataGrid)grid, e.Key);
        }

        private static bool IsLastFieldFocused(XamDataGrid grid)
        {
            var addRecord = GetAddRecord(grid);

            if (addRecord == null)
                return false;

            return grid.ActiveCell.Field.ActualPosition.Column ==
                   addRecord.FieldLayout.Fields.Where(f => f.Visibility == Visibility.Visible)
                   .Max(f => f.ActualPosition.Column);
        }

        private static DataRecord GetAddRecord(XamDataGrid grid)
        {
            foreach (DataRecord item in grid.RecordManager.DataPresenter.Records)
            {
                if (item.IsAddRecord)
                    return item;
            }

            return null;
        }
    }