Usually we pass the property name as string from the setter of properties and raise the INotifyPropertyChanged.PropertyChanged event.This is not type safe as you.There are chances that the end developers may misspell the property name.The below link gives a great idea to make your OnPropertyChanged calls type safe.
http://mfelicio.wordpress.com/2010/01/10/safe-usage-of-inotifypropertychanged-in-mvvm-scenarios/
