Is there a way to set the ZIndex of different ItemsControl within the same canvas

Question

I'm trying to set the ZIndex of different ItemsControls within a canvas and initially I did this which worked fine. Each of the following Collections was organised as expected.

 <ItemsControl ItemsSource="{Binding AllPoints.PointsObjects}" Panel.ZIndex={Binding ZIndex}>

 <ItemsControl ItemsSource="{Binding AllTracks.TrackObjects}" Panel.ZIndex={Binding ZIndex}>

However I need to be able to change the ZIndexes of each item within each ItemsControl individually. So I moved the ZIndex Binding to each individual object and tried to set the ZIndex using ItemsControl.ItemContainerStyle. But the collections did not appear in the order as expected.

                <ItemsControl ItemsSource="{Binding AllPoints.PointsObjects}">

                    <ItemsControl.Resources>
                        <!--Resource dictionary template-->
                    </ItemsControl.Resources>

                    <ItemsControl.ItemsPanel>
                        <ItemsPanelTemplate>
                            <Canvas />
                        </ItemsPanelTemplate>
                    </ItemsControl.ItemsPanel>


                    <ItemsControl.ItemContainerStyle>
                        <Style TargetType="{x:Type ContentPresenter}">
                            <Setter Property="Canvas.ZIndex" Value="{Binding ZIndex}"/>
                        </Style>
                    </ItemsControl.ItemContainerStyle>
                
                </ItemsControl>


                <ItemsControl ItemsSource="{Binding AllTracks.TrackObjects}">

                    <ItemsControl.Resources>
                        <!--Resource dictionary template-->
                    </ItemsControl.Resources>

                    <ItemsControl.ItemsPanel>
                        <ItemsPanelTemplate>
                            <Canvas />
                        </ItemsPanelTemplate>
                    </ItemsControl.ItemsPanel>


                    <ItemsControl.ItemContainerStyle>
                        <Style TargetType="{x:Type ContentPresenter}">
                            <Setter Property="Canvas.ZIndex" Value="{Binding ZIndex}"/>
                        </Style>
                    </ItemsControl.ItemContainerStyle>
                </ItemsControl>
               

Would I need to create just one ItemsControl or is it possible to link different ItemsControl's ZIndexes by use ItemsControl.ItemContainerStyle?

Answer 1

Following Clemens answer to my post this is the solution to my question. Within the Windows.Resources.

  <Window.Resources>
        <CollectionViewSource x:Key="Points" Source="{Binding AllPoints.PointsObjects}"/>
        <CollectionViewSource x:Key="Tracks" Source="{Binding AllTracks.TrackObjects}"/>
     

        <CompositeCollection x:Key="CombinedCollection">
            <CollectionContainer Collection="{Binding Source={StaticResource Points}}" />
            <CollectionContainer Collection="{Binding Source={StaticResource Tracks}}" />

        </CompositeCollection>
            
    </Window.Resources>

And within the Canvas.

<Canvas>
        <ItemsControl ItemsSource="{StaticResource CombinedCollection}">
                    <ItemsControl.ItemContainerStyle>
                        <Style TargetType="{x:Type ContentPresenter}">
                            <Setter Property="Panel.ZIndex" Value="{Binding ZIndex}"/>
                        </Style>
                    </ItemsControl.ItemContainerStyle>
                </ItemsControl>
</Canvas>