WPF Expander in Xaml?

I want to make an ItemsControl that provides some of its own children, and then when used can add additional children, similarly to the built in Expander class.

However, in this example, the Header TextBlock is also removed. This is a rephrasing of a question I asked yesterday.

LayerPanelItem.xaml:

<ItemsControl x:Class="Controls.LayerPanelItem"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">

    <StackPanel>
        <TextBlock>Header</TextBlock>
        <StackPanel Name="InnerContent">
            <!-- Tes开发者_如何学Pythont 1 and Test 2 should go here. -->
        </StackPanel>
    </StackPanel>

</ItemsControl>

Main.xaml:

<controls:LayerPanelItem>
    <TextBlock>Test 1</TextBlock>
    <TextBlock>Test 2</TextBlock>
</controls:LayerPanelItem>

If I'm understanding you correctly, you want more of a HeaderedItemsControl. Expander derives from HeaderedContentControl and this adds in the ItemsControl behavior to that:

<HeaderedItemsControl x:Class="WpfApplication1.LayerPanelItem"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <HeaderedItemsControl.Template>
        <ControlTemplate TargetType="{x:Type HeaderedItemsControl}">
            <StackPanel>
                <ContentPresenter ContentSource="Header"/>
                <ItemsPresenter/>
            </StackPanel>
        </ControlTemplate>
    </HeaderedItemsControl.Template>
    <HeaderedItemsControl.Header>
        <StackPanel>
            <TextBlock>Header</TextBlock>
            <TextBlock>Other stuff...</TextBlock>
        </StackPanel>
    </HeaderedItemsControl.Header>
</HeaderedItemsControl>