Access .resx string resource within xaml layout in uwp

I'd like to access resources directly in my xaml layout, and official doc give us some poor examples so I can't get it work. Suppose following Resources.resw :

I can access my string resources from C# class like so:

 var loader = new ResourceLoader();
 var resourceString = loader.GetString("txt_ok");

How can I access this resource in xaml for a TextBlock text for example?

<TextBlock
  x:Name="MyTextBox"
  Text="I want to get string resource here"/> 

I was trying some examples from here or here but no succes