GridView如何合并同类项

/// <summary>
    /// 合并GridView中某列相同信息的行（单元格）
    /// </summary>
    /// <param name="GridView1">GridView</param>
    /// <param name="cellNum">第几列</param>
    public static void GroupRows(GridView GridView1, int cellNum)
    {
        int i = 0, rowSpanNum = 1;
        while (i < GridView1.Rows.Count - 1)
        {
            GridViewRow gvr = GridView1.Rows[i];

for (++i; i < GridView1.Rows.Count; i++)
            {
                GridViewRow gvrNext = GridView1.Rows[i];
                if (gvr.Cells[cellNum].Text == gvrNext.Cells[cellNum].Text)
                {
                    gvrNext.Cells[cellNum].Visible = false;
                    rowSpanNum++;
                }
                else
                {
                    gvr.Cells[cellNum].RowSpan = rowSpanNum;
                    rowSpanNum = 1;
                    break;
                }

if (i == GridView1.Rows.Count - 1)
                {
                    gvr.Cells[cellNum].RowSpan = rowSpanNum;
                }
            }
        }
    }