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。
复制代码 代码如下:
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")%>' style="border: 0px;" src="/UploadFiles/2021-04-02/+.gif">
<!--下面这个绑定，是第一层显示的文字-->
<%# Eval("Year") & "年"%>
<div id='div<%# Eval("Year")%>' style="display: none;">

<!--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")%>' style="border: 0px; padding-left: 20px;" src="/UploadFiles/2021-04-02/+.gif"><%# Eval("Month") & "月"%>
<div id='div<%# Eval("Month")%>' style="display: none;">

<!--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;" src="/UploadFiles/2021-04-02/m_file.png"></ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
</div>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
</div>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>

复制代码 代码如下:
InsusMenu.ascx.vb

Imports System.Data
Imports Insus.NET

Partial 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 Sub
End Class