添加序号列

        SolidBrush solidBrush;        StringFormat stringFormat = new StringFormat();        private void Form36_Load(object sender, EventArgs e)        {            solidBrush = new SolidBrush(dataGridView1.RowHeadersDefaultCellStyle.ForeColor);            stringFormat.Alignment = StringAlignment.Center;//垂直居中            stringFormat.LineAlignment = StringAlignment.Center;//水平居中            stringFormat.FormatFlags = StringFormatFlags.NoWrap;//不自动换行            DataTable dataTable = new DataTable();            dataTable.Columns.Add("AA");            for (int i = 0; i < 111111; i++)            {                dataTable.Rows.Add(new object[] { i});            }            dataGridView1.DataSource = dataTable;            SetRowHeadersWidth();//在数据源改变或者行数有很大变化时调用这个方法        }        private void SetRowHeadersWidth()        {            int line = dataGridView1.Rows.Count;            Size size = TextRenderer.MeasureText(line.ToString(), dataGridView1.RowHeadersDefaultCellStyle.Font);//测试dataGridView1行数的宽度            dataGridView1.RowHeadersWidth = size.Width + 30;//设置左侧行的宽度        }        private void dataGridView1_RowPostPaint(object sender, DataGridViewRowPostPaintEventArgs e)        {            //在左侧行中间绘制            e.Graphics.DrawString((e.RowIndex + 1).ToString(),                e.InheritedRowStyle.Font,                solidBrush,                new Rectangle(e.RowBounds.X, e.RowBounds.Y, dataGridView1.RowHeadersWidth, e.RowBounds.Height),                stringFormat);        }