I want to raise PropertyChanged for all 20 Properties of my ViewModel in once and get the solution:
RaisePropertyChanged(String.Empty)
see: C#/WPF: PropertyChanged for all Properties in ViewModel?
Since I use GalaSoft.MvvmLight.ViewModelBase.RaisePropertyChanged of MVVM Light, I get the runtime error: 
   Message=Property not found
   ParamName=""
   Source=GalaSoft.MvvmLight.WPF4
This is because MVVM Light check all Property-Names.
What can I do?