Here is a try at this.
private void gridGroupingControl1_TableControlCellDrawn(object sender, GridTableControlDrawCellEventArgs e)
{
GridTableCellStyleInfo style = e.Inner.Style as GridTableCellStyleInfo;
if(style.TableCellIdentity.TableCellType == GridTableCellType.GroupIndentCell)
{
if(style.TableCellIdentity.DisplayElement is GridRecordRow)
{
using(Brush b = new SolidBrush(Color.Red))
{
GridRecordRow rec = style.TableCellIdentity.DisplayElement as GridRecordRow;
int i = rec.ParentGroup.Records.IndexOf(rec.ParentRecord);
e.Inner.Graphics.DrawString(i.ToString(), style.GdipFont, b,
e.Inner.Bounds.X + 2, e.Inner.Bounds.Y + 2);
e.Inner.Cancel = true;
}
}
}
}