How to reflect inheritance of classes in WPF/XAML?

c#, datatemplate, wpf, xaml

Solution

You could simply nest each base class `UserControl` inside more derived `UserControl`s, but you could find that this might soon become unmanageable. Another way would be to use the `ContentControl` element to display sections of larger `DataTemplate`s from other `DataTemplate`s like this:

<DataTemplate x:Key="NameTemplate" DataType="{x:Type ViewModels:UserViewModel}">
    <TextBlock Text="{Binding Name}" />
</DataTemplate>
...
<DataTemplate DataType="{x:Type ViewModels:UserDerivedViewModel}">
    <ContentControl Content="{Binding}" 
        ContentTemplate="{StaticResource NameTemplate}" />
    <TextBlock Text="{Binding Age}" />
</DataTemplate>

Problem

(First: I have some programming experience but am a beginner with XAML/WPF/StackOverflow. So please forgive anything "stupid" and ask if anything is not clearly described or you need additional info. Thanks.) Introduction: I have a base class `Item` with some properties (like `Title`, `Notes`, etc.). From that I have some derived classes like `ContactItem`, `MediaItem`, etc. with additional properties which act as base classes for further specialized item types (e.g. `ImageItem`, `MusicItem` and `VideoItem` which are derived from `MediaItem`; `Person` and `Institution` are derived from `ContactItem`). In WPF I want a page where multiple item types can be displayed together. I currently use an `ItemsPanel` for this and started to specify data templates for each item type - and there are many (more than 50). Problem: What I now want is some kind of "inheritance" of the item controls (e.g. have a "base" `UserControl` with a `ContentPresenter` and add additional controls for additional properties of derived classes/control templates). What would be the best way to handle this in WPF/XAML without having to copy/paste the controls from the base classes for the derived item types in the data templates? Any idea or hint in the right direction would be great. If you need some code or additional info, please let me know.

Original source