Canvas Z Order issue - wpf

Question

Im trying to render a bunch of ellipses with lines coming out from the center, in north, east, south and west directions.
However, I also need all ellipses to be on top of all lines, not just on top of its own lines.
With the following code, I can't do this as each item template has its own canvas, and so setting the zindex wont help.
Any ideas of how I could solve this?
<Window x:Class="WpfApplication27.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="800" Width="800">
<ItemsControl ItemsSource="{Binding Nodes}">
<ItemsControl.Template>
<ControlTemplate>
<Grid>
<Canvas Name="PART_Canvas" IsItemsHost="True"/>
</Grid>
</ControlTemplate>
</ItemsControl.Template>
<ItemsControl.ItemTemplate>
<DataTemplate>
<Canvas>
<Line X1="25" Y1="25" X2="25" Y2="125" Stroke="Black"/>
<Line X1="25" Y1="25" X2="25" Y2="-75" Stroke="Black"/>
<Line X1="25" Y1="25" X2="125" Y2="25" Stroke="Black"/>
<Line X1="25" Y1="25" X2="-75" Y2="25" Stroke="Black"/>
<Ellipse Width="50" Height="50" Fill="Red"/>
</Canvas>
</DataTemplate>
</ItemsControl.ItemTemplate>
<ItemsControl.ItemContainerStyle>
<Style TargetType="ContentPresenter">
<Setter Property="Canvas.Left" Value="{Binding X}"/>
<Setter Property="Canvas.Top" Value="{Binding Y}"/>
</Style>
</ItemsControl.ItemContainerStyle>
</ItemsControl>
</Window>

Answer 1

You could add 2 ItemsCotrols on top of each other bound to the same collection, the back one would render the lines and the front one renders the ellipse's
<Grid>
<Grid.Resources>
<Style x:Key="NodeContainer" TargetType="ContentPresenter">
<Setter Property="Canvas.Left" Value="{Binding X}"/>
<Setter Property="Canvas.Top" Value="{Binding Y}"/>
</Style>
</Grid.Resources>
<!--Line-->
<ItemsControl ItemsSource="{Binding Nodes}" ItemContainerStyle="{StaticResource NodeContainer}">
<ItemsControl.Template>
<ControlTemplate>
<Grid>
<Canvas Name="PART_CanvasBack" IsItemsHost="True"/>
</Grid>
</ControlTemplate>
</ItemsControl.Template>
<ItemsControl.ItemTemplate>
<DataTemplate>
<Canvas>
<Line X1="25" Y1="25" X2="25" Y2="125" Stroke="Black"/>
<Line X1="25" Y1="25" X2="25" Y2="-75" Stroke="Black"/>
<Line X1="25" Y1="25" X2="125" Y2="25" Stroke="Black"/>
<Line X1="25" Y1="25" X2="-75" Y2="25" Stroke="Black"/>
</Canvas>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
<!--Ellipse-->
<ItemsControl ItemsSource="{Binding Nodes}" ItemContainerStyle="{StaticResource NodeContainer}">
<ItemsControl.Template>
<ControlTemplate>
<Grid>
<Canvas Name="PART_CanvasFront" IsItemsHost="True"/>
</Grid>
</ControlTemplate>
</ItemsControl.Template>
<ItemsControl.ItemTemplate>
<DataTemplate>
<Canvas>
<Ellipse Width="50" Height="50" Fill="Red"/>
</Canvas>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</Grid>