application keep light theme on mojave dark mode

Hello, how can I keep application ui as it was before "mojave" dark mode? As I found I have to set theme from appdelegate, but in xamarin I'm not able to do this, because 'ThemeManager' is not visible in app :

[Export("applicationWillFinishLaunching:")] public void WillFinishLaunching(NSNotification notification) { //ThemeManager.lightTheme.apply() }

Is there any way to disable 'dark mode' for whole application in xamarin.mac?

thanks