public HeaderRegionViewModel(IHeaderRegionController controller, IEventAggregator eventAggregator)
 {
     _controller = controller;
     _eventAggregator = eventAggregator;
 }
 public FrameworkController(IEventAggregator eventAggregator, IHeaderRegionController headerRegionController, IMenuRegionController menuRegionController)
 {
     _eventAggregator = eventAggregator;
     _headerRegion = headerRegionController;
     _menuRegion = menuRegionController;
 }