Is PropertyChanged += LinkLabel_PropertyChanged; same as protected override void OnPropertyChanged(string propertyName = null) - xamarin

Question

In a Xamarin template like this. I think there are two ways to check if a property has changed.
Adding PropertyChanged += LinkLabel_PropertyChanged;
Overriding, calling base
If I want to do something when more than one property has changed is there any difference between these two ways of calling a method?
public class LinkLabel : Label
{
public LinkLabel()
{
PropertyChanged += LinkLabel_PropertyChanged;
}
protected override void OnPropertyChanged(string propertyName = null)
{
base.OnPropertyChanged(propertyName);
// Check property name and do action here
}
private void LinkLabel_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
// Check property name and do action here
}
}
For reference here is what I coded and I am wondering if that's a good solution:
public class LinkLabel : Label
{
public LinkLabel()
{
SetDynamicResource(Label.FontFamilyProperty, "Default-Regular");
SetDynamicResource(Label.FontSizeProperty, "LabelTextFontSize");
SetDynamicResource(Label.TextColorProperty, "LinkLabelColor");
VerticalOptions = LayoutOptions.CenterAndExpand;
VerticalTextAlignment = TextAlignment.Center;
}
public static readonly BindableProperty IsImportantProperty =
BindableProperty.Create(nameof(IsImportant), typeof(bool), typeof(LinkLabel), false);
public bool IsImportant
{
get { return (bool)GetValue(IsImportantProperty); }
set { SetValue(IsImportantProperty, value); }
}
protected override void OnPropertyChanged(string propertyName = null)
{
base.OnPropertyChanged(propertyName);
if (propertyName == IsEnabledProperty.PropertyName ||
propertyName == IsImportantProperty.PropertyName)
{
if (this.IsEnabled) {
if (this.IsImportant)
this.SetDynamicResource(Label.TextColorProperty, "LinkLabelImportantColor");
else
this.SetDynamicResource(Label.TextColorProperty, "LinkLabelColor");
}
else
this.SetDynamicResource(Label.TextColorProperty, "LinkLabelDisabledColor");
}
}
}

Answer 1

Yes, the difference is that registering for the PropertyChanged event works from outside, overriding the protected(!) OnPropertyChanged method works only from within derived classes of Label.
So you would normally only create a new derived LinkLabel class if you want to change the behavior of the label. There, you'd override the OnPropertyChanged (if you need to).
If you want to get informed about a change in your main form, you would register the event directly there. No need to create a derived class.