Sample Uno Platform project for demonstrating Uno Platform RequestedTheme bug.
Repository is referencing to this issue.
RequestedTheme works for application:
<Application RequestedTheme="Dark" >
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="Themes/PurpleTheme.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
</Application>But not working with UIElement:
<NavigationView RequestedTheme="Light">
<NavigationView.Resources>
<ResourceDictionary Source="Themes/PurpleTheme.xaml"/>
</NavigationView.Resources>
</NavigationView>