Repeater inside repeater not binding properly - asp.net

Question

I have a repeater inside another. Like so :
<asp:Repeater ID="CategoryRepeater" runat="server" OnItemDataBound="ItemBound">
<ItemTemplate>
<div class="groupbox">
<fieldset>
<legend><%# Container.DataItem %></legend>
<table>
<asp:Repeater ID="ItemRepeater" runat="server">
<ItemTemplate>
<tr>
<td>
<asp:CheckBox id="chkItem" runat="server" Text='<%# Eval("Text")%>' />
<asp:Button ID="btnXRefs" Text="x-refs" runat="server" CssClass="xRefButton" OnClick="btnSelectXRefs_Click" />
</td>
</tr>
</ItemTemplate>
</asp:Repeater>
</table>
</fieldset>
</div>
</ItemTemplate>
</asp:Repeater>
CODE BEHIND :
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
using (var db = new DbContext())
{
CategoryRepeater.DataSource = db.Categories.OrderBy(x => x.Heading).Select(x => x.Heading).Distinct();
CategoryRepeater.DataBind();
}
}
}
protected void ItemBound(object sender, RepeaterItemEventArgs args)
{
if (args.Item.ItemType == ListItemType.Item)
{
Repeater childRepeater = (Repeater)args.Item.FindControl("ItemRepeater");
var item = args.Item as RepeaterItem;
using (var db = new DbContext())
{
childRepeater.DataSource = db.Categories.Where(x => x.Heading == item.DataItem).OrderBy(x => x.Text);
childRepeater.DataBind();
}
}
}
My goal is to first make many groupboxes using the top level, then bind items into each one. So I end up with many small stacked lists of checkboxes.
Problem is, all the top level boxes appear, yet only the first one contains checkbox items, ie. only the first one is bound internally, and the ItemBound method is only called once for the first one.
Any ideas why?

Answer 1

This line
if (args.Item.ItemType == ListItemType.Item)
Should be like this
if(args.Item.ItemType = ListItemType.Item ||
args.Item.ItemType == ListItemType.AlternatingItem)