GridView多层嵌套和折叠与展开

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。

<%@ 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="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")%>' 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="Image/+.gif" onclick="ShowHidde('<%#Eval("Month")%>',event)" />
                                    <%# 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;  16px; height: 16px; vertical-align: middle;" src="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>

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