If you would like to change the background of your WP7 app based on whether the user has selected the light or dark theme, you can determine if the user has selected the dark or light theme using code such as the following. I use this in a shared WP7 helper library amongst all of my apps:
public static bool IsLightTheme()
{
Color LightThemeBackground = Color.FromArgb(255, 255, 255, 255);
SolidColorBrush backgroundBrush = Application.Current.Resources["PhoneBackgroundBrush"] as SolidColorBrush;
if (backgroundBrush.Color == LightThemeBackground)
{
return true;
}
else
{
return false;
}
}
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