DataGridRow 显示datagrid行数，不过会加慢速度

 public class  DataGridRow : DataGrid
 {
  protected override  void OnPaint(PaintEventArgs e)

  {

   base.OnPaint(e);

   try

   {

    if(this.DataSource!=null)

    {          

     int yDelta;

     System.Drawing .Rectangle cell=this.GetCellBounds(0,0);

     int y=cell.Top +2;

     e.Graphics.DrawString("", this.Font, new SolidBrush(Color.Black), 8, y-18); //

     if(this.VisibleRowCount >0)//只在有记录集时在表格中显示序号

     {                  

      CurrencyManager cm;

      cm = (CurrencyManager) this.BindingContext[this.DataSource, this.DataMember];

      if(cm.Count >0)

      {                      

       int nRow=-1;

       y=41;           //为第一行默认高度

       while(nRow<0)

       {

        nRow=this.HitTest (8,y).Row ;

        y++;

       }

       int nCount=0;

       while(y<this.Height && nCount<this.VisibleRowCount )

       {

        string text = string.Format("{0}", nRow+nCount+1);

        e.Graphics.DrawString(text, this.Font, new SolidBrush(Color.Black), 10, y);

        yDelta = this.GetCellBounds( nRow+nCount,0).Height + 1;//****表示一行高度的参数

        y += yDelta;

        //如果下面有子行显示序号的区分显示  

        if(this.IsExpanded (nRow+nCount)&& nRow+nCount+1<cm.Count )                                
        {

         y+=this.GetCellBounds (nRow+nCount+1,0).Height +3;

        }

        nCount++;      

       }

      }

     }

    }

   }

   catch

   {}

  }

调用继承他就可以了