添加一行

int index=this.dataGridView1.Rows.Add();
this.dataGridView1.Rows[index].Cells[0].Value = “1”;
this.dataGridView1.Rows[index].Cells[1].Value = “2”;
this.dataGridView1.Rows[index].Cells[2].Value = “3”;

加上序号

private void dataGridView1_RowPostPaint(object sender, DataGridViewRowPostPaintEventArgs e)

    {
        SolidBrush b = new SolidBrush(this.dataGridView1.RowHeadersDefaultCellStyle.ForeColor);
        e.Graphics.DrawString((e.RowIndex + 1).ToString(System.Globalization.CultureInfo.CurrentUICulture), this.dataGridView1.DefaultCellStyle.Font, b, e.RowBounds.Location.X + 20, e.RowBounds.Location.Y + 4);


    }