Question

I am trying to create custom templated control based on a ListBox to display only the single selected item in the control’s collection.
To this aim, I have defined a Template with an ContentPresenter, databound to the SelectedItem property of the control.
As illustrated in scenario 1, it works well when providing the control with a collection of UIElement.

But when needing to use a DataTemplate to display an entity object, the ItemTemplate is ignored because the control has a Template which will prevent the `ItemTemplate from being used. From what I’ve read this is by design and it sorts of makes sense.

But how can I use DataTemplates for my control’s ItemTemplate and retain my control default template?

I have tried overriding PrepareContainerForItemOverride, and many different template configurations to no avail.

Here is some of what I tried:

<UserControl.Resources>

    <local:StringCollection x:Key="MyColors">
        <sys:String>Yellow</sys:String>
        <sys:String>Purple</sys:String>
    </local:StringCollection>

</UserControl.Resources>

<StackPanel Background="White">

    <TextBlock Margin="0,25,0,0">Scenario 1: Providing UIElements to the
        ControlTemplate's ContentPresenter: Works</TextBlock>
    <control:RotatingFlipView x:Name="Works" SelectedIndex="1">
        <control:RotatingFlipView.Template>
            <ControlTemplate>
                <ContentPresenter
                     Content="{Binding ElementName=Works, Path=SelectedItem}"/>
            </ControlTemplate>
        </control:RotatingFlipView.Template>
        <Rectangle Height="100" Width="100" Fill="Red"/>
        <Rectangle Height="100" Width="100" Fill="Blue"/>
        <Rectangle Height="100" Width="100" Fill="Green"/>
    </control:RotatingFlipView>

    <TextBlock Margin="0,25,0,0">Scenario 2: The ItemTemplate provided is ignored in
        favor of the RotatingFlipView's Template which displays the source as raw
        Strings</TextBlock>
    <control:RotatingFlipView x:Name="Broken"
                              ItemsSource="{StaticResource MyColors}">
        <control:RotatingFlipView.Template>
            <ControlTemplate>
                <ContentPresenter
                    Content="{Binding ElementName=Broken, Path=SelectedItem}"/>
            </ControlTemplate>
        </control:RotatingFlipView.Template>
        <control:RotatingFlipView.ItemTemplate>
            <DataTemplate>
                <Rectangle Height="100" Width="100" Fill="{Binding}"/>
            </DataTemplate>
        </control:RotatingFlipView.ItemTemplate>
    </control:RotatingFlipView>

    <TextBlock Margin="0,25,0,0">Scenario 3: Removing the RotatingFlipView's
        Template, causes the display to fall back on the ListBox's Template,
        though now my ItemTemplate is used:</TextBlock>
    <control:RotatingFlipView x:Name="Broken2"
                              ItemsSource="{StaticResource MyColors}">
        <control:RotatingFlipView.ItemTemplate>
            <DataTemplate>
                <Rectangle Height="100" Width="100" Fill="{Binding}"/>
            </DataTemplate>
        </control:RotatingFlipView.ItemTemplate>
    </control:RotatingFlipView>

</StackPanel>

RotatingFlipView.cs

public class RotatingFlipView : ListBox
{
    public RotatingFlipView()
    {
        DefaultStyleKey = typeof(RotatingFlipView);
    }
}

generic.xaml

<Style TargetType="local:RotatingFlipView">
    <Setter Property="SelectionMode" Value="Single"/>
    <Setter Property="SelectedIndex" Value="0"/>
</Style>

Output:

Answer 1

I have now figured it out. Here is how I’ve done it:

Mainpage.xaml

<UserControl.Resources>

    <local:StringCollection x:Key="MyColors">
        <sys:String>Yellow</sys:String>
        <sys:String>Purple</sys:String>
    </local:StringCollection>

</UserControl.Resources>

<StackPanel Background="White">
    <control:RotatingFlipView>
        <Rectangle Height="100" Width="100" Fill="Red"/>
        <Rectangle Height="100" Width="100" Fill="Green"/>
        <Rectangle Height="100" Width="100" Fill="Blue"/>
    </control:RotatingFlipView>

    <control:RotatingFlipView ItemsSource="{StaticResource MyColors}">
        <control:RotatingFlipView.ItemTemplate>
            <DataTemplate>
                <Rectangle Height="100" Width="100" Fill="{Binding}"/>
            </DataTemplate>
        </control:RotatingFlipView.ItemTemplate>
    </control:RotatingFlipView>
<StackPanel/>

RotatingFlipView.cs

public class RotatingFlipView : ListBox    
{    
    public RotatingFlipView()    
    {    
        DefaultStyleKey = typeof(RotatingFlipView);    
    }    
}

generic.xaml

<Style TargetType="local:RotatingFlipView">
    <Setter Property="SelectionMode" Value="Single"/>
    <Setter Property="SelectedIndex" Value="0"/>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="local:RotatingFlipView">

                <ContentPresenter
                    Content="{TemplateBinding SelectedItem}"
                    ContentTemplate="{TemplateBinding ItemTemplate}"/>

            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>