Question

In my UI code I have a lot classes with the same basic skeleton:

• derives from INotifyPropertyChanged

• contains the following code:

  void NotifyPropertyChanged(String info)
  {
      if (PropertyChanged != null)
      {
          PropertyChanged(this, new PropertyChangedEventArgs(info));
      }
  }
  
  public event PropertyChangedEventHandler PropertyChanged;
  

It seems like a perfect chance to factor into a class and to derive from that instead of INotifyPropertyChanged, but sadly C# doesn’t support multiple inheritance so it’s not really going to work. Any ideas on how to refactor this kind of code?

Answer 1

Can’t you just put this code into your superclass’s superclass?

• Object
  • Your concrete NotifyPropertyChanged class <– Insert here
    • Whatever your viewmodel inherited from (and stopped you using multiple inheritance
      • Your concrete viewmodel
      • Another concrete viewmodel

Most MVVM Frameworks provide such a class for you.

Because of the access rules around events, you can’t factor this out into an extension method without reflection, unfortunately.