public void UpdateDependencies(INotifyExpressionChanged source, string propertyName)
 {
     foreach (var dexp in _dependencyMap.Values)
     {
         foreach (var d in dexp.Dependencies)
         {
             if (d == propertyName)
             {
                 source.NotifyPropertyChanged(dexp.Name);
             }
         }
     }
 }
 public void Uninitialize(INotifyExpressionChanged source)
 {
     source.PropertyChanged -= OnPropertyChanged;
 }