repeater相同行合并

<table  width="100%"    id="mytable" >
    <tr align="center">
      <th>学号</th><th>姓名</th><th>起止时间</th> <th>学习(或工作)单位</th> <th>职务</th> <th>证明人</th> <th>备注</th>
    </tr>
    <asp:Repeater ID="Repeater1" runat="server" onprerender="Repeater1_PreRender">
    <ItemTemplate>
    <tr><td id="tdxuehao" runat="server">&nbsp;<%#Eval("xuehao") %></td><td id="tdxsname" runat="server">&nbsp;<%#Eval("xsname")%></td><td>&nbsp;<%#Eval("qzsj")%></td> <td>&nbsp;<%#Eval("grjl")%></td> <td>&nbsp;<%#Eval("zw")%></td> <td>&nbsp;<%#Eval("zmr")%></td> <td>&nbsp;<%#Eval("bz")%></td>
    </tr>
    </ItemTemplate>
    </asp:Repeater>
    
       </table>

protected void Repeater1_PreRender(object sender, EventArgs e)
        {
            for (int i = Repeater1.Items.Count - 1; i > 0; i--)
            {
                //tcid是需要合并列的列名
                HtmlTableCell oCell_previous = Repeater1.Items[i - 1].FindControl("tdxuehao") as HtmlTableCell;
                HtmlTableCell oCell = Repeater1.Items[i].FindControl("tdxuehao") as HtmlTableCell;
                if (oCell_previous != null && oCell != null)
                {
                    oCell.RowSpan = (oCell.RowSpan == -1) ? 1 : oCell.RowSpan;
                    oCell_previous.RowSpan = (oCell_previous.RowSpan == -1) ? 1 : oCell_previous.RowSpan;

                    if (oCell.InnerText == oCell_previous.InnerText)
                    {
                        oCell.Visible = false;
                        oCell_previous.RowSpan += oCell.RowSpan;
                    }
                }


                HtmlTableCell nameprevious = Repeater1.Items[i - 1].FindControl("tdxsname") as HtmlTableCell;
                HtmlTableCell name = Repeater1.Items[i].FindControl("tdxsname") as HtmlTableCell;
                if (nameprevious != null && name != null)
                {
                    name.RowSpan = (name.RowSpan == -1) ? 1 : name.RowSpan;
                    nameprevious.RowSpan = (nameprevious.RowSpan == -1) ? 1 : nameprevious.RowSpan;

                    if (name.InnerText == nameprevious.InnerText)
                    {
                        name.Visible = false;
                        nameprevious.RowSpan += name.RowSpan;
                    }
                }
            }


        }