private static void OnUserChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
{
UserSelector self = (UserSelector)obj;
self.User.Content = self.SelectedUserName;
var path = String.Format("./cache/u{0}_avatar.jpg", self.SelectedUserId);
ImageHelper.LoadImage(self.Avatar, path, "Assert/ic_account_circle_white_48dp.png");
self.DecreaseIndexButton.IsEnabled = !self.IsFirst;
self.IncreaseIndexButton.IsEnabled = !self.IsLast;
self.RaiseUserChangedEvent();
}
