检查所选的dataGridView行是否为粗体

我有一段需要更改为常规字体并从跟踪器中删除。我需要它检查行是否粗体，但它失败了。

private void clientDataGridView_SelectionChanged(object sender, EventArgs e)
    {
        foreach (DataGridViewRow row in clientDataGridView.SelectedRows)
        {
            if (row.DefaultCellStyle.Font.Style == FontStyle.Bold)
            {
                row.DefaultCellStyle.Font = new Font(DefaultFont, FontStyle.Regular);
                new_tracker --;
            }
            idtxt.Text = row.Cells[0].Value.ToString();
            emailtxt.Text = row.Cells[1].Value.ToString();
            nametxt.Text = row.Cells[2].Value.ToString();
            packagetxt.Text = row.Cells[3].Value.ToString();
            notificationToolStripStatusLabel.Text = "0 new notifications";
        }
    }

if (row == null) result = "row is null";
else if (!row.HasDefaultCellStyle) result  = "no row style";      // this helps!
else if (row.DefaultCellStyle.Font == null) result  = "no font";  // may work without
else if (row.DefaultCellStyle.Font.Bold) result  = "bold";