C#DataGridView合计处理

网上查了一些关于合计的代码 ，但发现大都都不尽人意，就自己再根据资料改了一下。

#region 合计
            //调用方法示例
            //HeJi heji = null;
            //heji = new HeJi(label1,dataGridView1);
            //heji.AddHeji("FTransportOperator_ID",4);
            //heji.AddHeji("FLoadingTeam_ID",6);
            //heji.sumdata();
            
    public class HeJi
    {
        
        //两个控件 文本，表格
        private Label Lab1;
        private DataGridView Grid;
        //定义类的私有变量，两个是滚动条
        HScrollBar hs;
        VScrollBar vs;

        //合计的信息列表
        List<HeJiMessage> li = new List<HeJiMessage>();

        //初始化
        public HeJi() { }
        public HeJi(Label lab, DataGridView grid) 
        {
            Lab1 = lab;
            Grid = grid;

            hs = ((HScrollBar)this.Grid.Controls[0]);
            vs = ((VScrollBar)this.Grid.Controls[1]);
            hs.ValueChanged += new EventHandler(hs_ValueChanged);
            vs.ValueChanged += new EventHandler(vs_ValueChanged);
            Lab1.Paint += new PaintEventHandler(Lab_Paint);
            Grid.CellValueChanged += new DataGridViewCellEventHandler(CellValueChanged);
        }
        //滚动条委托事件
        public void hs_ValueChanged(object sender, EventArgs e)
        {
            this.Lab1.Invalidate();
        }
        public void vs_ValueChanged(object sender, EventArgs e)
        {
            this.Lab1.Invalidate();
        }

        /// <summary>
        /// 表格数值改变
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void CellValueChanged(object sender, DataGridViewCellEventArgs e)
        {
            sumdata();
        }

        /// <summary>
        /// //添加需要合计的列
        /// </summary>
        /// <param name="name">字段名</param>
        /// <param name="number">列索引</param>
        public void AddHeji(string name, int number)
        {
            Rectangle rec = this.Grid.GetCellDisplayRectangle(number, 0, false);
            li.Add(new HeJiMessage(name, number,rec));
        }

        /// <summary>
        /// paint委托事件，重画
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Lab_Paint(object sender, PaintEventArgs e)
        {
            DataGridViewColumnCollection Columns = this.Grid.Columns;
            int count = Grid.Columns.Count;
            Graphics grf = e.Graphics;
            StringFormat strfmt = new StringFormat();
            strfmt.Alignment = StringAlignment.Center;
            //判断有显示的行，利用行获取Rectangle位置信息
            foreach (HeJiMessage heji in li)
            {
                Rectangle rec = this.Grid.GetCellDisplayRectangle(heji.CellNumber, 0, false);
                for (int i = 0; i < Grid.Rows.Count; i++)
                {
                    if (Grid.Rows[i].Displayed)
                    {
                        rec = this.Grid.GetCellDisplayRectangle(heji.CellNumber, i, false);
                        heji.Rec = rec;
                        Console.WriteLine("显示行为：" + i.ToString());
                        break;
                    }
                }
                grf.DrawString(string.Format("{0:F2}",heji.hejiSum ), this.Lab1.Font, Brushes.Black, this.Grid.Left + heji.Rec.X, 3, strfmt);
            }          
        }

        //计算总和
        public void sumdata()
        {
           
            DataGridViewRowCollection rows = this.Grid.Rows;
            foreach (HeJiMessage heji in li)
            {
                heji.hejiSum = 0;             
                foreach (DataGridViewRow row in rows)
                {
                    heji.hejiSum += Convert.ToDecimal(row.Cells[heji.hejiName].Value);                   
                }
            }
          
            //重画
            this.Lab1.Invalidate();
        }
    }

    //合计需要的信息，列名，列索引，总和，位置信息
    public class HeJiMessage
    {
       public  string hejiName = null;
       public int CellNumber = 0;
       public decimal hejiSum = 0;
       public Rectangle Rec;
       public HeJiMessage() { }
        /// <summary>
        /// 初始化
        /// </summary>
        /// <param name="name">列名</param>
        /// <param name="number">列索引</param>
        /// <param name="rec">位置信息</param>
       public HeJiMessage(string name, int number,Rectangle rec)
        {
            hejiName = name;
            CellNumber = number;
            Rec = rec;
        }
    }

#endregion