I have this piece of code (or similar) in many of our views: private IEventAggregator eventAggregator; Constructor() { eventAggregator = ServiceLocator.Current.GetInstance<IEventAggregator>(); ... } I read from this post that ServiceLocator.Current can throw NullReferenceException (bad thing on a constructor) but I was wondering if the GetInstance<() method can return null (or some other inconsistent object) making eventAggregator dangerous to use later in other methods. NOTE: I'm quite new to MVVM and WPF