Comments on: INotifyPropertyChanged Snippets (And Why You Should Use These Instead of DependencyProperties)

By: Denis Vuyka

Denis Vuyka — Sat, 16 May 2009 05:59:13 +0000

I agree with Clayton Firth. This is a violation of pattern not checking the value being actually changed before raising notifications. There may be many components bound to this property or listening to property change notifications. You will make a great performance impact or push UI editors into the endless loop of updates and as a result StackOverflow exception.
Checking the property value is a mandatory part of this pattern.

By: Steve

Steve — Fri, 01 May 2009 17:00:49 +0000

You shouldn’t give a new collection as default value for your dependency property. Create a new instance in the ctor and there should be no problem.

By: Matthias Shapiro

Matthias Shapiro — Fri, 01 May 2009 04:16:15 +0000

I assume that by “actually changes”, you mean that the new value is different than the old value (even if the value changed in the sense that it was re-set). What you have works for me…

By: Clayton Firth

Clayton Firth — Fri, 01 May 2009 03:52:15 +0000

What is you opinion of checking if the property “actually” changes? I would normally add the following code.

if(!_myProperty.Equals(value))
{
_myProperty = value;
RaisePropertyChanged(“MyProperty”);
}