WPF How to set focus to next cell in datagrid

PreviewKeyDown(object sender, KeyEventArgs e)
{
  DataGrid grid = (DataGrid)sender;

  if (e.Key == Key.Enter || e.Key == Key.Return)
  {
    // get the selected row
    var selectedRow = grid.ItemContainerGenerator.ContainerFromItem(grid.SelectedItem) as DataGridRow;

    // selectedRow can be null due to virtualization
    if (selectedRow != null)
    {
      // there should always be a selected cell
      if (grid.SelectedCells.Count != 0)
      {
         // get the cell info
         DataGridCellInfo currentCell = grid.SelectedCells[0];

         // get the display index of the cell's column + 1 (for next column)
         int columnDisplayIndex = currentCell.Column.DisplayIndex++;

         // if display index is valid
         if (columnDisplayIndex < grid.Columns.Count)
         {
            // get the DataGridColumn instance from the display index
            DataGridColumn nextColumn = grid.ColumnFromDisplayIndex(columnDisplayIndex);

            // now telling the grid, that we handled the key down event
            e.Handled = true;

            // setting the current cell (selected, focused)
            grid.CurrentCell = new DataGridCellInfo(grid.SelectedItem, nextColumn);

            // tell the grid to initialize edit mode for the current cell
            grid.BeginEdit();
         }
      }
    }
  }
}