решено
private void Dgv_CellPainting(object sender, DataGridViewCellPaintingEventArgs e)
{
if (e.ColumnIndex == -1 && e.RowIndex > -1)
{
object o = (sender as DataGridView).Rows[e.RowIndex].HeaderCell.Value;
e.PaintBackground(e.CellBounds, true);
using (SolidBrush br = new SolidBrush(Color.Black))
{
StringFormat sf = new StringFormat();
sf.Alignment = StringAlignment.Center;
sf.LineAlignment = StringAlignment.Center;
e.Graphics.DrawString(o.ToString(),
e.CellStyle.Font, br, e.CellBounds, sf);
}
e.Handled = true;
}
}
