DataGridView显示行号

可以做成扩展控件，这里是主要代码:

方法一：

private void dataGridView2_RowPostPaint(object sender, DataGridViewRowPostPaintEventArgs e)
        {
            using (var brush = new SolidBrush(dataGridView2.RowHeadersDefaultCellStyle.ForeColor))
            {
                e.Graphics.DrawString((e.RowIndex + 1).ToString(), dataGridView2.DefaultCellStyle.Font, brush, e.RowBounds.Location.X + 12, e.RowBounds.Y + 5);
            }
        }

方法二：

private void dataGridView1_CellPainting(object sender, DataGridViewCellPaintingEventArgs e)
        {
            if (e.ColumnIndex == -1 && e.RowIndex >= 0 && e.RowIndex < dataGridView1.Rows.Count)
            {
                //dataGridView1.Rows[e.RowIndex].HeaderCell.Value = (e.RowIndex).ToString();
                e.PaintBackground(e.ClipBounds, true);
                e.Graphics.DrawString((e.RowIndex + 1).ToString(), Font, Brushes.Black, e.CellBounds.Left + 6,
                                      e.CellBounds.Top + 5);
                e.Handled = true;
            }
        }

方法三：继承DataGridView扩展为自定义控件

public partial class DataGridViewEx : DataGridView
    {
        bool showRowHeaderNumbers;

        /// <summary>
        /// 是否显示行号
        /// </summary>
        [Category("扩展属性"), Description("是否显示行号"), DefaultValue(false)]
        public bool ShowRowHeaderNumbers
        {
            get { return showRowHeaderNumbers; }
            set
            {
                if (showRowHeaderNumbers != value)
                    Invalidate();
                showRowHeaderNumbers = value;
            }
            //get;
            //set;
        }

        public DataGridViewEx()
        {
            InitializeComponent();
        }

        protected override void OnRowPostPaint(DataGridViewRowPostPaintEventArgs e)
        {
            if (ShowRowHeaderNumbers)
            {
                string title = (e.RowIndex + 1).ToString();
                Brush brush = Brushes.Black;
                e.Graphics.DrawString(title, DefaultCellStyle.Font, brush, e.RowBounds.Location.X + RowHeadersWidth / 2 - 4, e.RowBounds.Location.Y + 4);
            }

            base.OnRowPostPaint(e);
        }
    }