public DataGridCell GetCell(int row, int column)
    {
        DataGridRow rowContainer = GetRow(row);

        if (rowContainer != null)
        {
            DataGridCellsPresenter presenter = GetVisualChild<DataGridCellsPresenter>(rowContainer);

            DataGridCell cell = (DataGridCell)presenter.ItemContainerGenerator.ContainerFromIndex(column);
            if (cell == null)
            {
                datagrid_arinc_const.ScrollIntoView(rowContainer, datagrid_arinc_const.Columns[column]);
                cell = (DataGridCell)presenter.ItemContainerGenerator.ContainerFromIndex(column);
            }
            return cell;
        }
        return null;
    }

    public DataGridRow GetRow(int index)
    {
        DataGridRow row = (DataGridRow)datagrid_arinc_const.ItemContainerGenerator.ContainerFromIndex(index);
        if (row == null)
        {
            datagrid_arinc_const.UpdateLayout();
            datagrid_arinc_const.ScrollIntoView(datagrid_arinc_const.Items[index]);
            row = (DataGridRow)datagrid_arinc_const.ItemContainerGenerator.ContainerFromIndex(index);
        }
        return row;
    }

    public static T GetVisualChild<T>(Visual parent) where T : Visual
    {
        T child = default(T);
        int numVisuals = VisualTreeHelper.GetChildrenCount(parent);
        for (int i = 0; i < numVisuals; i++)
        {
            Visual v = (Visual)VisualTreeHelper.GetChild(parent, i);
            child = v as T;
            if (child == null)
            {
                child = GetVisualChild<T>(v);
            }
            if (child != null)
            {
                break;
            }
        }
        return child;
    }

<DataGrid VirtualizingStackPanel.IsVirtualizing="False"/>