本文实例讲述了C#实现DataList里面嵌套DataList的折叠菜单。分享给大家供大家参考，具体如下：
点击前效果图如下：
点击后效果图如下：
具体实现代码如下：
Javascript脚本
<script type="text/javascript">
function showmenu(id)
{
smallimg = eval("smallimg"+id);
img =eval("img"+id);
if(smallimg.style.display =="none")
{
eval("smallimg"+id+".style.display=\"\";");//全部显示
img.src="Image/tree_folder3.gif";//显示为-
}
else
{
eval("smallimg"+id+".style.display=\"none\";"); //全部隐藏
img.src="Image/tree_folder4.gif";//显示为+
}
}
</script>
HTML代码如下：
<body>
<form id="Form1" method="post" runat="server">
<font face="宋体"></font>
<table width="679" height="100%" border="0" cellpadding="0" cellspacing="0" align="center">
<tr>
<td align="center" valign="top">
<strong>版块 设 置</strong>
<br />
<br />
管理选项：<asp:Button ID="btnAdd" runat="server"
OnClick="btnAdd_Click" Text="添加一级版块"/><br />
<br />
<asp:DataList ID="DataList1" runat="server" CellSpacing="0" CellPadding="0" Width="679"
OnItemDataBound="DataList1_ItemDataBound">
<HeaderTemplate>
<table width="679" border="0" cellpadding="0" cellspacing="0" bgcolor="#000000" class="border">
<tr bgcolor="#a4b6d7" class="title">
<td height="25" align="center">
<strong>版块名称</strong></td>
<td height="20" align="center">
<strong>操作选项</strong></td>
</tr>
</HeaderTemplate>
<ItemTemplate>
<tr bgcolor="ECF5FF" class="tdbg">
<td height="22" width="50%">
<img id="img<%#Eval("BigClassID")%>" src="Image/tree_folder4.gif" width="15" height="15" onclick="showmenu(<%#Eval("BigClassID")%>)"><%#Eval("BigClassName")%></td>
<td align="center" width="50%">
<a href='SmallClassAdd.aspx?BigClassID=<%#Eval("BigClassID")%>'>
添加二级版块</a> | <a href='BigClassModify.aspx?BigClassID=<%#Eval("BigClassID")%>'>
修改一级版块</a> | <a href='BigClassDelete.aspx?BigClassID=<%#Eval("BigClassID")%>'
onclick="return confirm('确定删除吗,下级版块及相关帖子都将被删除,且不可恢复!!!')">删除一级版块</a></td>
</tr>
<tr bgcolor="ECF5FF" class="tdbg" width="100%">
<td colspan="2" width="100%">
<asp:DataList ID='dlstSmallClass' EnableViewState='false' runat='server'>
<HeaderTemplate>
<table width="679" border="0" cellpadding="0" cellspacing="0" bgcolor="#000000" class="border">
</HeaderTemplate>
<ItemTemplate>
<tr id="smallimg<%#Eval("BigClassID")%>" style="display:none" bgcolor="#E3E3E3" class="tdbg">
<td height="22" width="50%" colspan="3">
<img src="Image/tree_folder3.gif" width="15" height="15"><%#Eval("SmallClassName")%></td>
<td align="center" width="50%" colspan="3">
<a href='SmallClassModify.aspx?SmallClassID=<%#Eval("SmallClassID")%>'>
修改二级版块</a> | <a href='SmallClassDelete.aspx?SmallClassID=<%#Eval("SmallClassID")%>'
onclick="return confirm('确定删除吗,相关帖子都将被删除,且不可恢复!!!')">删除二级版块</a></td>
</tr>
</ItemTemplate>
<FooterTemplate>
</table>
</FooterTemplate>
</asp:DataList>
</td>
</tr>
</ItemTemplate>
<FooterTemplate>
</table>
</FooterTemplate>
</asp:DataList>
</td>
</tr>
</table>
</form>
</body>
上面的功能有点缺陷（ques1:多行时候不能折叠，默认只折叠第一行；ques2:不支持IE），现在改善如下：
<script type="text/javascript">
function showmenu(id)
{
var smallimg = document.getElementById("smallimg"+id);
var img = document.getElementById("img"+id);
if(smallimg.style.display =="none")
{
smallimg.style.display="";
img.src="Image/tree_folder3.gif";//显示为-
}
else
{
smallimg.style.display ="none";
img.src="Image/tree_folder4.gif";//显示为+
}
}
</script>
<body>
<form id="Form1" method="post" runat="server">
<font face="宋体"></font>
<table width="679" height="100%" border="0" cellpadding="0" cellspacing="0" align="center">
<tr>
<td align="center" valign="top">
<strong>版 块 设 置</strong>
<br />
<br />
管理选项：<asp:Button ID="btnAdd" runat="server" OnClick="btnAdd_Click" Text="添加一级版块"/><br />
<br />
<asp:DataList ID="DataList1" runat="server" CellSpacing="0" CellPadding="0" Width="679"
OnItemDataBound="DataList1_ItemDataBound">
<HeaderTemplate>
<table width="679" border="0" cellpadding="0" cellspacing="0" bgcolor="#000000"class="border">
<tr bgcolor="#a4b6d7"class="title">
<td height="25" align="center">
<strong>版块名称</strong>
</td>
<td height="20" align="center">
<strong>操作选项</strong>
</td>
</tr>
</HeaderTemplate>
<ItemTemplate>
<tr bgcolor="ECF5FF"class="tdbg">
<td height="22" width="50%">
<img id="img<%#Eval("BigClassID")%>" src="Image/tree_folder4.gif" width="15" height="15"
onclick="showmenu(<%#Eval("BigClassID")%>)"><%#Eval("BigC <td align="center" width="50%" colspan="3">
<a href='SmallClassModify.aspx?SmallClassID=<%#Eval("SmallClassID")%>'>
修改二级版块</a>|<a href='SmallClassDelete.aspx?SmallClassID=<%#Eval("SmallClassID")%>'
onclick="return confirm('确定删除吗,相关帖子都将被删除,且不可恢复!!!')">删除二级版块</a>
</td>
</tr>
</ItemTemplate>
<FooterTemplate>
</table>
</FooterTemplate>
</asp:DataList>
</td>
</tr>
</ItemTemplate>
<FooterTemplate>
</table>
</FooterTemplate>
</asp:DataList>
</td>
</tr>
</table>
</form>
</body>
希望本文所述对大家C#程序设计有所帮助。