同一值标识同一颜色

dataGridView1.Rows[0].DefaultCellStyle.BackColor = Color.White;
            Color tempColor = Color.AntiqueWhite;
            bool b = true;//标示
            for (int j = 1; j < dataGridView1.Rows.Count; j++)
            {
                if (dataGridView1.Rows[j].Cells[1].Value.ToString() == dataGridView1.Rows[j - 1].Cells[1].Value.ToString())
                {
                    dataGridView1.Rows[j].DefaultCellStyle.BackColor = dataGridView1.Rows[j - 1].DefaultCellStyle.BackColor;
                }
                else
                {
                    if (b)
                    {
                        dataGridView1.Rows[j].DefaultCellStyle.BackColor = tempColor;
                        tempColor = Color.White;
                        b = false;
                    }
                    else
                    {
                        dataGridView1.Rows[j].DefaultCellStyle.BackColor = tempColor;
                        tempColor = Color.AntiqueWhite;
                        b = true;
                    }
                }
            }