This blog post is going to teach you how do we detect if we are on dark or light theme on Windows Phone 7. I realised that this will be useful because I have quite some friends who are asking me about it because they didn’t get the right resources online. If you happened to come across a resource that asks you to get from App.xaml, that doesnt work anymore as its removed after the RC build.

Based on Theme Resources for Windows Phone, under Theme Visibility and Opacity.
By checking Resources, I am able to check if its Visible or Collapsed for the dark or White theme by doing this

Visibility isLight = (Visibility)Resources[“PhoneLightThemeVisibility”]; // for light theme
Visibility isDark = (Visibility)Resources[“PhoneDarkThemeVisibility”]; // for dark theme

Then we use if else to check,

if (isLight == System.Windows.Visibility.Visible)
{
//We are on light theme
}

Light Theme

or

if (isDark == System.Windows.Visibility.Visible)
{
//We are on dark theme
}

Dark Theme

Attached is a sample code to show how do I detect Windows Phone 7 theme, before the Mango buuild ( I am unsure if there is a change after Mango ).
Detect Theme on Windows Phone 7 Sample