winfrom 最左侧的，我想绘制序列

代码如下：

private void dataGridView1_RowPostPaint(object sender, DataGridViewRowPostPaintEventArgs e)
{
DataGridView dg = (DataGridView)sender;
System.Drawing.Rectangle rectangle = new System.Drawing.Rectangle(e.RowBounds.Location.X,

e.RowBounds.Location.Y,

dg.RowHeadersWidth,

e.RowBounds.Height);

TextRenderer.DrawText(e.Graphics, (e.RowIndex + 1).ToString(),

dg.RowHeadersDefaultCellStyle.Font,

rectangle,

dg.RowHeadersDefaultCellStyle.ForeColor,

TextFormatFlags.VerticalCenter | TextFormatFlags.Right);
}

但是里面的星号还在，怎去掉*号？