里面的exception ex 中的ex代表什么？还需要添加以下代码吗

//int i = dataGridView1.CurrentCell.RowIndex;
//DataRow dr = ds.Tables["DressingWheel"].Rows[i];
//dr["修整轮名称"] = dataGridView1.CurrentRow.Cells[0].Value.ToString();
////dr["修整轮名称"] = dataGridView1.Rows [i].Cells[0].Value.ToString();
//dr["修整轮直径"] = dataGridView1.CurrentRow.Cells[1].Value.ToString();
//dr["修整轮圆角半径R1"] = dataGridView1.CurrentRow.Cells[2].Value.ToString();
//dr["修整轮圆角半径R2"] = dataGridView1.CurrentRow.Cells[3].Value.ToString();
//dr["距离L1"] = dataGridView1.CurrentRow.Cells[4].Value.ToString();
//dr["距离L2"] = dataGridView1.CurrentRow.Cells[5].Value.ToString();
//dr["修整轮修整高度H"] = dataGridView1.CurrentRow.Cells[6].Value.ToString();