Setting Canvas properties in an ItemsControl DataTemplate

Question

I'm trying to databind to this ItemsControl:

<ItemsControl ItemsSource="{Binding Path=Nodes, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}">
    <ItemsControl.ItemsPanel>
        <ItemsPanelTemplate>
            <Canvas />
        </ItemsPanelTemplate>
    </ItemsControl.ItemsPanel>
</ItemsControl>

By using this DataTemplate, I'm trying to individually position my Node elements on the Canvas correctly:

<DataTemplate DataType="{x:Type Model:EndNode}">
    <Controls:EndNodeControl Canvas.Left="{Binding Path=XPos}" Canvas.Top="{Binding Path=YPos}" />
</DataTemplate>

However, it's not working as expected. All my node elements are drawn on top of each other in the same position. Any suggestions on how to accomplish this?

Answer 1

The attached properties only work on direct children of the Canvas. ItemsControl will place ContentPresenter controls as its direct children, so you might want to add a style for that as well:

<ItemsControl ItemsSource="{Binding Path=Nodes}">
    <ItemsControl.ItemsPanel>
        <ItemsPanelTemplate>
            <Canvas />
        </ItemsPanelTemplate>
    </ItemsControl.ItemsPanel>
    <ItemsControl.ItemContainerStyle>
        <Style TargetType="ContentPresenter">
            <Setter Property="Canvas.Left" Value="{Binding Path=XPos}" />
            <Setter Property="Canvas.Top" Value="{Binding Path=YPos}" />
        </Style>
    </ItemsControl.ItemContainerStyle>
</ItemsControl>