Data-based template selection in WPF - wpf

Question

I have this simple XAML example:
<Window x:Class="DynTemplateTest.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="300" Width="300">
<Window.Resources>
<DataTemplate x:Key="ItemTemplate">
<ItemsControl ItemsSource="{Binding}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Rectangle Width="30" Height="30" Fill="Red"></Rectangle>
</DataTemplate>
</ItemsControl.ItemTemplate>
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<Canvas />
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.ItemContainerStyle>
<Style>
<Setter Property="Canvas.Left" Value="{Binding Position}"></Setter>
</Style>
</ItemsControl.ItemContainerStyle>
</ItemsControl>
</DataTemplate>
</Window.Resources>
<DockPanel LastChildFill="True">
<ContentPresenter
Content="{Binding Path=Items}"
ContentTemplate="{StaticResource ItemTemplate}"
>
</ContentPresenter>
</DockPanel>
</Window>
It is rendering my items in the observable collection in MVVM style. Each item is having its horizontal position in a property. Each item also has a property IsSpecial which tells if it wants to be rendered in some special way. I want ordinary items (IsSpecial=false) render as red squares (already in the code) and special items as blue circles with "special" text inside.
What I do not know is how to adjust the XAML code to do the template selection for the items. Is there a way to do that without coding my own ItemTemplateSelector? Will it still work with the canvas positioning based on binding. I think that the solution is to extract the item template to a separate template, create one more template for special items and then somehow play with triggers ... but it is not very easy for me as I am a WPF beginner at the moment.
The other thing is that I quite dislike the way how the Position is passed to the items. Is there some other way?
Are there any other recommendations how to improve the code?

Answer 1

I solved it myself :D
<Window x:Class="DynTemplateTest.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="300" Width="300">
<Window.Resources>
<DataTemplate x:Key="NormalItem">
<Rectangle Width="30" Height="30" Fill="Red"></Rectangle>
</DataTemplate>
<DataTemplate x:Key="SpecialItem">
<Rectangle Width="30" Height="30" Fill="Red"></Rectangle>
</DataTemplate>
<DataTemplate x:Key="ItemTemplate">
<ItemsControl ItemsSource="{Binding}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<ContentControl Content="{Binding}" ContentTemplate="{StaticResource NormalItem}" x:Name="ItemsContentControl" />
<DataTemplate.Triggers>
<DataTrigger Binding="{Binding Path=IsSpecial}" Value="true">
<Setter TargetName="ItemsContentControl" Property="ContentTemplate" Value="{StaticResource SpecialItem}" />
</DataTrigger>
</DataTemplate.Triggers>
</DataTemplate>
</ItemsControl.ItemTemplate>
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<Canvas />
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.ItemContainerStyle>
<Style>
<Setter Property="Canvas.Left" Value="{Binding Position}" />
</Style>
</ItemsControl.ItemContainerStyle>
</ItemsControl>
</DataTemplate>
</Window.Resources>
<DockPanel LastChildFill="True">
<ContentPresenter
Content="{Binding Path=Items}"
ContentTemplate="{StaticResource ItemTemplate}"
>
</ContentPresenter>
</DockPanel>
</Window>
But still, any thoughts on alternatives or improvements?