public MainViewModel(IRegionManager _regionManager, MainModel _model) { RegionManager = _regionManager; Model = _model.AddTo(DisposeCollection); Model.IsSelected.Skip(1).Subscribe(item => { var param = new NavigationParameters(); param.Add(nameof(Sample), item.Sample); RegionManager.RequestNavigate("ContentRegion", item.ViewName, param); }).AddTo(DisposeCollection); }