private void NotifyStateChange()
{
// Most of these properties change together as a
// group, so we've grouped all the updates in this function.
// It might make sense later to put them in a different place.
RaisePropertyChanged("IsFormEditable");
RaisePropertyChanged("LoginHeader");
RaisePropertyChanged("LoginText");
RaisePropertyChanged("LoginButtonText");
RaisePropertyChanged("IsProcessing");
RaisePropertyChanged("ErrorMessage");
RaisePropertyChanged("ErrorMessageVisible");
RaisePropertyChanged("Username");
RaisePropertyChanged("Password");
Login.RaiseCanExecuteChanged();
}