INotifyPropertyChanged1.cs

public class MyViewModel : INotifyPropertyChanged
{
  public event PropertyChangedEventHandler PropertyChanged = delegate {};

  string _name;
  public string Name
  {
    get { return _name; }
    set
    {
      if (_name == value) return
      _name = value;
      PropertyChanged(this, new PropertyChangedEventArgs("Name"));
    }
  }
}

INotifyPropertyChanged2.cs

public class MyViewModel : INotifyPropertyChanged
{
  public event PropertyChangedEventHandler PropertyChanged = delegate {};

  string _name;
  public string Name
  {
    get { return _name; }
    set
    {
      if (_name == value) return
      _name = value;
      RaiseNotifyPropertyChanged();
    }
  }
  
  void RaiseNotifyPropertyChanged([CallerMemberName]string propertyName = null)
  {
      PropertyChanged(this, new PropertyChangedEventArgs("Name"));
  }
}

INotifyPropertyChanged3.cs

public class MyViewModel : NotifyPropertyChanged
{
  string _name;
  public string Name
  {
    get { return _name; }
    set
    {
      if (_name == value) return
      _name = value;
      RaiseNotifyPropertyChanged();
    }
  }
}

// This is utility code that you could share with the world.
abstract class NotifyPropertyChanged : INotifyPropertyChanged
{
  public event PropertyChangedEventHandler PropertyChanged = delegate {};

  void RaiseNotifyPropertyChanged([CallerMemberName]string propertyName = null)
  {
      PropertyChanged(this, new PropertyChangedEventArgs("Name"));
  }
}