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PODisplaying an IGrouping<> with nested ListViews
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  1. PODisplaying an IGrouping<> with nested ListViews
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    copied!<p>I need to retrieve a set of Widgets from my data access layer, grouped by widget.Manufacturer, to display in a set of nested ASP.NET ListViews.</p> <p>The problem is that (as far as I can tell) the nested ListView approach requires me to shape the data before using it, and I can't figure out the best approach to take. The best I've been able to come up with so far is to put a LINQ query in my data access layer like so:</p> <pre><code>var result = from widget in GetAllWidgets(int widgetTypeID) group widget by widget.Manufacturer into groupedWidgets let widgets = from widgetGroup in groupedWidgets select widgetGroup select new { Manufacturer = groupedWidgets.Key, Widgets = widgets }; </code></pre> <p>Of course, anonymous types can't be passed around, so that doesn't work. Defining a custom class to enclose data seems like the wrong way to go. Is there some way I can perform the grouping on the ASP.NET side of things? I'm using ObjectDataSources to access the DAL.</p> <p><b>Updated</b>: OK, I'm not creating an anonymous type anymore, and instead my DAL passes an <code>IEnumerable&lt;IGrouping&lt;Manufacturer, Widget&gt;&gt;</code> to the ASP.NET page, but how can I use this in my ListViews? I need to render the following HTML (or something pretty much like it)</p> <pre><code>&lt;ul&gt; &lt;li&gt;Foo Corp. &lt;ol&gt; &lt;li&gt;Baz&lt;/li&gt; &lt;li&gt;Quux&lt;/li&gt; &lt;/ol&gt; &lt;/li&gt; &lt;li&gt;Bar Corp. &lt;ol&gt; &lt;li&gt;Thinger&lt;/li&gt; &lt;li&gt;Whatsit&lt;/li&gt; &lt;/ol&gt; &lt;/li&gt; &lt;/ul&gt; </code></pre> <p>Originally, I had a ListView within a ListView like so:</p> <pre><code>&lt;asp:ListView ID="ManufacturerListView"&gt; &lt;LayoutTemplate&gt; &lt;ul&gt; &lt;asp:Placeholder ID="itemPlaceholder" runat="server" /&gt; &lt;/ul&gt; &lt;/LayoutTemplate&gt; &lt;ItemTemplate&gt; &lt;li&gt;&lt;asp:Label Text='&lt;%# Eval("Manufacturer.Name") %&gt;' /&gt; &lt;li&gt; &lt;asp:ListView ID="WidgetsListView" runat="server" DataSource='&lt;%# Eval("Widgets") %&gt;'&gt; &lt;LayoutTemplate&gt; &lt;ol&gt; &lt;asp:PlaceHolder runat="server" ID="itemPlaceholder" /&gt; &lt;/ol&gt; &lt;/LayoutTemplate&gt; &lt;ItemTemplate&gt; &lt;li&gt;&lt;asp:Label Text='&lt;%# Eval("Name") %&gt;'&gt;&lt;/li&gt; &lt;/ItemTemplate&gt; &lt;/asp:ListView&gt; &lt;/li&gt; &lt;/ItemTemplate&gt; &lt;/asp:ListView&gt; </code></pre> <p>Note how the <code>DataSource</code> property of WidgetsListView is itself databound. How can I duplicate this functionality without reshaping the data?</p> <p>This is getting kind of complicated, sorry if I should have just made a separate question instead.</p>
 

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