How to make a footer section on a hierarchical data template

I am trying to implement a treeView that has a footer section at the bottom of each hierarchy so a user can easily add items to the bottom.

Something like

    <TreeView>
        <TreeView.Resources>
            <HierarchicalDataTemplate DataType="local:MyNestedType"
                                      ItemsSource="{Binding Items}">
                <StackP开发者_运维问答anel>
                   <Label Content="{Binding NodeName}" /> 
                    <!--Nested Items here-->
                    <Button Content="Add New Item" />
                </StackPanel>
            </HierarchicalDataTemplate>
        </TreeView.Resources>
    </TreeView>

How can I achieve this.

The answer isn't pretty, but it is doable.

You'll have to override the ItemContainerStyle of the TreeView, and define a control template.

http://msdn.microsoft.com/en-us/library/ms788727.aspx

In that example, you'll see that the TreeViewItem control template has some XAML like this:

<Grid>
  <Grid.ColumnDefinitions>
    <ColumnDefinition MinWidth="19" Width="Auto"/>
    <ColumnDefinition Width="Auto"/>
    <ColumnDefinition Width="*"/>
  </Grid.ColumnDefinitions>
  <Grid.RowDefinitions>
    <RowDefinition Height="Auto"/>
    <RowDefinition/>
  </Grid.RowDefinitions>
  <ToggleButton x:Name="Expander"
          Style="{StaticResource ExpandCollapseToggleStyle}"
          IsChecked="{Binding Path=IsExpanded,
                      RelativeSource={RelativeSource TemplatedParent}}"
          ClickMode="Press"/>
  <Border Name="Bd"
      Grid.Column="1"
      Background="{TemplateBinding Background}"
      BorderBrush="{TemplateBinding BorderBrush}"
      BorderThickness="{TemplateBinding BorderThickness}"
      Padding="{TemplateBinding Padding}">
    <ContentPresenter x:Name="PART_Header"
              ContentSource="Header"
              HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"/>
  </Border>
  <ItemsPresenter x:Name="ItemsHost"
          Grid.Row="1"
          Grid.Column="1"
          Grid.ColumnSpan="2"/>
</Grid> 

That XAML defines how child items are shown relative to the parent item - under the ItemsPresenter you could insert your footer.