Setting Default theme for appbar in windows phone 7

  var phoneAccentBrush = new SolidColorBrush((App.Current.Resources["PhoneAccentBrush"] as SolidColorBrush).Color);
            this.ApplicationBar.BackgroundColor = Color.FromArgb(phoneAccentBrush.Color.A, phoneAccentBrush.Color.R, phoneAccentBrush.Color.G, phoneAccentBrush.Color.B);