public AViewModel(IBusServiceModel busServiceModel, IAppDataModel appDataModel, ILocationModel locationModel) { this.lazyBusServiceModel = busServiceModel; this.lazyAppDataModel = appDataModel; if (!IsInDesignMode) { locationTracker = new LocationTracker(); operationTracker = new AsyncOperationTracker(); } // Set up the default action, just execute in the same thread UIAction = (uiAction => uiAction()); eventsRegistered = false; }