Insus.NET近段时间应朋友的要求，写一个GridView多层嵌套和折叠与展开。这个功能的GridView多层嵌套没有问题，因为已经做了无限次数，但是折叠与展开的功能，却花上不少时间(网上找资料)，虽找到资料可参考，还是了解明它，并修改适合自己程序使用。效果如下：

站点中多个页面使用，因此Insus.NET把它写在一个用户自定义控件ASCX上。

InsusMenu.ascx

<%@ Control Language="VB" AutoEventWireup="false" CodeFile="InsusMenu.ascx.vb" Inherits="AscxControls_InsusMenu" %><!--折叠与展开的Javascript部分--><script type="text/javascript" language="javascript">    function ShowHidde(sid, evt) {        evt = evt || window.event;        var target = evt.target || evt.srcElement;        var objDiv = document.getElementById("div" + sid);        objDiv.style.display = objDiv.style.display == "none" ? "block" : "none";        target.title = objDiv.style.display == "none" ? "Show" : "Hide";        var imgid = 'img' + sid;        document.getElementById(imgid).src = objDiv.style.display == "none" ? "Image/+.gif" : "Image/-.gif";    }</script><!--第一层--><asp:GridView ID="GridViewYear" runat="server" Width="100%" AutoGenerateColumns="False"    OnRowDataBound="GridViewYear_RowDataBound" ShowHeader="false" BorderWidth="0">    <Columns>        <asp:TemplateField>            <ItemStyle BorderWidth="0" Height="25" />            <ItemTemplate>                 <!--下在这个绑定Eval("Year")，是为获取唯一ID，如果你的记录有一个主键的话，可以绑定主键的字段名-->                <img id='img<%# Eval("Year")%>'  class="lazyload" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC" data-original="Image/+.gif" onclick="ShowHidde('<%#Eval("Year")%>',event)" />                                               <!--下面这个绑定，是第一层显示的文字-->                 <%# Eval("Year") & "年"%>                <div id='div<%# Eval("Year")%>' >                                        <!--第二层-->                    <asp:GridView ID="GridViewMonth" runat="server" OnRowDataBound="GridViewMonth_RowDataBound" Width="100%" AutoGenerateColumns="False" ShowHeader="False" BorderWidth="0">                        <Columns>                            <asp:TemplateField>                                <ItemStyle BorderWidth="0" Height="25" />                                <ItemTemplate>                                   <!--这部分的解释，可参考上面。-->                                                                         <img id='img<%# Eval("Month")%>'  class="lazyload" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC" data-original="Image/+.gif" onclick="ShowHidde('<%#Eval("Month")%>',event)" />                                    <%# Eval("Month") & "月"%>                                    <div id='div<%# Eval("Month")%>' >                                                                               <!--第三层-->                                         <asp:GridView ID="GridViewVideoFile" runat="server" Width="100%" AutoGenerateColumns="False"                                            ShowHeader="False" BorderWidth="0">                                            <Columns>                                                <asp:TemplateField>                                                    <ItemStyle BorderWidth="0" Height="25" />                                                    <ItemTemplate>                                                        <img style="border: 0px; padding-left: 40px; padding-right:5px; width: 16px; height: 16px; vertical-align: middle;" class="lazyload" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC" data-original="Image/m_file.png" /><asp:HyperLink ID="HyperLinkPlayer" runat="server" NavigateUrl='<%# "~/VideoPlayer.aspx?videokey=" & Eval("VideoLibrary_nbr")%>' Text='<%# Eval("OldFileName").Substring(0, Eval("OldFileName").LastIndexOf("."))%>' Target="_blank"></asp:HyperLink>                                                    </ItemTemplate>                                                </asp:TemplateField>                                            </Columns>                                        </asp:GridView>                                    </div>                                </ItemTemplate>                            </asp:TemplateField>                        </Columns>                    </asp:GridView>                </div>            </ItemTemplate>        </asp:TemplateField>    </Columns></asp:GridView>

InsusMenu.ascx.vb

Imports System.DataImports Insus.NETPartial Class AscxControls_InsusMenu    Inherits System.Web.UI.UserControl    '宣告实例    Dim objVideoLibrary As New VideoLibrary()    Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load        If Not IsPostBack Then            Data_Binding()        End If    End Sub    Private Sub Data_Binding()        '从数据库获取数据，绑定在第一层的GridView        Me.GridViewYear.DataSource = objVideoLibrary.GetYear()        Me.GridViewYear.DataBind()    End Sub    '数据绑定在第二层的GridView    Protected Sub GridViewYear_RowDataBound(sender As Object, e As GridViewRowEventArgs)        Dim dvr As DataRowView = DirectCast(e.Row.DataItem, DataRowView)        If e.Row.RowType = DataControlRowType.DataRow Then            If e.Row.FindControl("GridViewMonth") IsNot Nothing Then                Dim Gv As GridView = DirectCast(e.Row.FindControl("GridViewMonth"), GridView)                objVideoLibrary.Year = ConvertData.ToSmallInt(dvr("Year"))                Gv.DataSource = objVideoLibrary.GetMonthByYear()                Gv.DataBind()            End If        End If    End Sub    '数据绑定在第三层的GridView    Protected Sub GridViewMonth_RowDataBound(sender As Object, e As GridViewRowEventArgs)        Dim dvr As DataRowView = DirectCast(e.Row.DataItem, DataRowView)        If e.Row.RowType = DataControlRowType.DataRow Then            If e.Row.FindControl("GridViewVideoFile") IsNot Nothing Then                Dim Gv As GridView = DirectCast(e.Row.FindControl("GridViewVideoFile"), GridView)                objVideoLibrary.Year = ConvertData.ToSmallInt(dvr("Year"))                objVideoLibrary.Month = ConvertData.ToTinyInt(dvr("Month"))                Gv.DataSource = objVideoLibrary.GetByYearAndMonth()                Gv.DataBind()            End If        End If    End SubEnd Class