ASP.NET VB Nested Listviews - asp.net

Question

I have an outer listview and inside its itemtemplate an inner listview. Each has its own SQLDataSource. A Id field from the outerlistview works as a select parameter for the second listview.
When stepping through with the debugger it works perfectly, unfortunately the rendered page only contains data from the outer listview. It appears the databinding of the outer listview fires and renders the page (including the inner listview) before the codebehind can provide a where parameter to the second listview.
The aspx page is below.
<%# Page Title="Nested ListView" Language="VB" MasterPageFile="~/MasterPages/SimpleMasterPage.master"
CodeFile="NLV2PA_A.aspx.vb" Inherits="Demos_NLV2PA_A" %>
<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="Server">
<asp:ListView ID="ListView1" runat="server" ItemPlaceholderID="PlaceHolder1" DataKeyNames="Id"
DataSourceID="SqlDataSource1">
<LayoutTemplate>
<asp:PlaceHolder runat="server" ID="PlaceHolder1"></asp:PlaceHolder>
</LayoutTemplate>
<EmptyDataTemplate>
<span>ListView 1 No data was returned. </span>
</EmptyDataTemplate>
<ItemTemplate>
<span style="">Id:
<asp:Label ID="IdLabel" runat="server" Text='<%# Eval("Id") %>' />
<br />
Name:
<asp:Label ID="NameLabel" runat="server" Text='<%# Eval("Name") %>' />
<br />
<br />
</span>
<asp:ListView ID="ListView2" runat="server" ItemPlaceholderID="PlaceHolder2" DataSourceID="SqlDataSource2">
<LayoutTemplate>
<asp:PlaceHolder runat="server" ID="PlaceHolder2"></asp:PlaceHolder>
</LayoutTemplate>
<EmptyDataTemplate>
<span>ListView2 No data was returned. </span>
</EmptyDataTemplate>
<ItemTemplate>
<span style="">Title:
<asp:Label ID="TitleLabel" runat="server" Text='<%# Eval("Title") %>' />
<br />
<h1>
<%# Eval("Title") %></h1>
<br />
Summary:
<asp:Label ID="SummaryLabel" runat="server" Text='<%# Eval("Summary") %>' />
<br />
PhotoAlbumID:
<asp:Label ID="PhotoAlbumIdLabel" runat="server" Text='<%# Eval("PhotoAlbumId") %>' />
<br />
<br />
</span>
</ItemTemplate>
</asp:ListView>
</ItemTemplate>
</asp:ListView>
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:RenaissanceConnectionString1 %>"
SelectCommand="SELECT [Id], [Name] FROM [PhotoAlbum] ORDER BY [Id]"></asp:SqlDataSource>
<asp:SqlDataSource ID="SqlDataSource2" runat="server" ConnectionString="<%$ ConnectionStrings:RenaissanceConnectionString1 %>"
SelectCommand="SELECT [Title], [Summary], [PhotoAlbumId] FROM [Apartments] WHERE ([PhotoAlbumId] = #PAId)">
<SelectParameters>
<asp:ControlParameter ControlID="ListView1" DefaultValue="0" Name="PAId" PropertyName="SelectedValue"
Type="Int32" />
</SelectParameters>
</asp:SqlDataSource>
</asp:Content>
The code behind is
Protected Sub ListView1_ItemDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.ListViewItemEventArgs) Handles ListView1.ItemDataBound
If e.Item.ItemType = ListViewItemType.DataItem Then
SqlDataSource2.SelectParameters("PAId").DefaultValue = DirectCast(e.Item.FindControl("IdLabel"), Label).Text
End If
End Sub
The output to the browser is:
Id: 8
Name: First set of Photos
ListView2 No data was returned.
Id: 9
Name: Second set of Photos
ListView2 No data was returned.
etc.
Microsoft make the point in an old article that:
You could, in theory, intercept the
ItemDataBound event of the parent
ListView, walk your way through the
control tree, grab a reference to the
child ListView, and bind it
programmatically to data. If you do,
you won't throw an exception, but the
binding command on the inner ListView
is lost because it fires too late to
affect the rendering.
Unfortunately, they don't tell me how to fix it.
If there is any genius out there who could tell me how to get this to work it would be much appreciated.

Answer 1

Put your SqlDataSource2 inside the ItemTemplate of ListView1.
for your ControlParameter, set ControlID="IdLabel" and PropertyName="Text"
You wont need any code behind