Multiple Undos for data grid view table

private void btn_Undo_Click(object sender, EventArgs e) //To Undo previous searched record
        {
            if (_dataSet != null && _dataSet.Tables.Count > 0 && _lastDtTable2 != null)
            {
                _dataSet.Tables.Clear();
                _dataSet.Tables.Add(_lastDtTable2);
                dataGridView1.DataSource = _dataSet.Tables[0];
            }
        }

Hi Can anyone help me ?

How do I make the above code to multiple undos ? It canm only be undo once now T___T