dataGridView.Rows[i].Cells[3].Value 的值如何转换为整数进行加法运算

sql = " insert into plankDetail3L (批号,明细号,材料名,高,宽,厚,块数) values(""" +
                               strOrderId + """," +
                              dataGridView3.Rows[i].Cells[1].Value + ",""" +
                              dataGridView3.Rows[i].Cells[2].Value + """," +
                              Convert.ToInt32(dataGridView3.Rows[i].Cells[3].Value) + intHeight + "," +
                              Convert.ToInt32(dataGridView3.Rows[i].Cells[4].Value) + intWidth + "," +
                              Convert.ToInt32(dataGridView3.Rows[i].Cells[5].Value) + intDeep + "," +
                              Convert.ToInt32(dataGridView3.Rows[i].Cells[6].Value) + ")";
                            OBJcmdUpdate3 = new OleDbCommand(sql, sqlConn);
                            OBJcmdUpdate3.ExecuteNonQuery();