detect Theme in Windows Phone app

How to get current accent color

//Accent color is given by PhoneAccentColor ressource. Its type is System.Windows.Media.Color
 using System.Windows.Media;
 
Color AccentColor() 
{
     return (Color)Application.Current.Resources["PhoneAccentColor"];
}

//To make a TextBlock theme-aware use the Style property
<TextBlock Style="{StaticResource PhoneTextAccentStyle}"/>

//To make a Rectangle theme-aware use the Fill property:
<Rectangle Fill="{StaticResource PhoneAccentBrush}" />

How to get current theme background

//To get theme background, you can use PhoneDarkThemeVisibility resource. Its type is System.Windows.Visibility enum

using System.Windows
 
bool DarkThemeUsed ()
{ 
     return Visibility.Visible ==   (Visibility)Application.Current.Resources["PhoneDarkThemeVisibility"];
}
 
bool LightThemeUsed() 
{
     return Visibility.Visible == (Visibility)Application.Current.Resources["PhoneLightThemeVisibility"];
}
 
...
 
 // Write the theme background value. 
 if (DarkThemeUsed ())  
{ 
    //Set resources according to dark theme 
 }
else 
{  
     //Set resources according to light theme
 }