Implementing INotifyPropertyChanged with a TabControl

I was reviewing this INotifyPropertyChanged example on MSDN. I have a tab control with multiple tabs. I want to use INotifyPropertyChanged on each tabpage by setting it up so when the user selects the tab it checks to see what has changed (because the user might not go through the tabs in order). How would I implement something like this? I guess what I'm trying to ask is once you have this:

private string propertyName;
public event PropertyChangedEventHandler PropertyChanged;

protected void OnPropertyChanged(string propertyName)
{
      PropertyChangedEventHandler handler = PropertyChanged;
      if (handler != null)
      {
            handler(this, new PropertyChangedEventArgs(propertyName));
      }
}

how do would I have the tabpage call OnPropertyChanged so that I can know which tab has been changed? 

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-- Tyler Hughes