Binding null Content in ContentControl
<p>I have ContentControl and my DataTemplateSelector support also null value.</p>

<pre><code>&lt;ContentControl Content="{x:Bind CurrentItem, Mode=OneWay}"&gt;
    &lt;ContentControl.DataTemplateSelector&gt;
        &lt;my:DataTemplateSelector&gt;
            &lt;my:DataTemplateSelector.NullTemplate&gt;
                &lt;DataTemplate&gt;
                    &lt;Border Background="Red" /&gt;
                &lt;/DataTemplate&gt;
            &lt;/my:DataTemplateSelector.NullTemplate&gt;
            &lt;my:DataTemplateSelector.CustomTemplate1&gt;
                &lt;DataTemplate&gt;
                    &lt;Border Background="Green" /&gt;
                &lt;/DataTemplate&gt;
            &lt;/my:DataTemplateSelector.CustomTemplate1&gt;
            &lt;my:DataTemplateSelector.CustomTemplate2&gt;
                &lt;DataTemplate&gt;
                    &lt;Border Background="Blue" /&gt;
                &lt;/DataTemplate&gt;
            &lt;/my:DataTemplateSelector.CustomTemplate2&gt;
        &lt;/my:DataTemplateSelector&gt;
    &lt;/ContentControl.DataTemplateSelector&gt;                
&lt;/ContentControl&gt;
</code></pre>

<p>The problem is that when CurrentItem changes to null, it doesn't call SelectTemplateCore method in DataTemplateSelector. Actually NullTemplate is select only when control is loaded first time and CurrentItem is null.</p>

<p>I can replace null value with dummy object but it's much more difficult to deal with this problem.
I have found <a href="https://stackoverflow.com/a/1219553/1933104">this</a> solution but it's only for WPF (UWP doesn't have Style.Triggers)</p>