Unable to insert UserControl

[AghaKhan]

I created a UserControl

<blazor:BlazorWebView x:Name="BlazorWebView" >
<usercontrols:DigitalClock />
</blazor:BlazorWebView>

In your code you are not running WPF app(BlazorWebViewTutorial.WpfApp) , rather BlazorWebViewTutorial.Shared App.
You will get exception at Window_ContentRendered.
Kindly show where you are real XAML file.