将DataGridView中的RowHeader中的三角号去除

protected override void OnCellPainting(DataGridViewCellPaintingEventArgs e)
{
    if (e.ColumnIndex < 0 && e.RowIndex >= 0 && e.RowIndex < this.Rows.Count)
    {
        StringFormat sf = new StringFormat();
        sf.Alignment = StringAlignment.Center;

        e.PaintBackground(e.ClipBounds, true);
        e.CellBounds.Y += 5; //垂直居中

        e.Graphics.DrawString((e.RowIndex + 1).ToString(), this.Font, Brushes.Black, e.CellBounds, sf);
        e.Handled = true;
    }
}