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);
        }
    }