Build and filter an event stream using Rx

Rx events

Items = new List<FacetViewModel<T>>(names.Select(n => CreateFacetViewModel(n, displayExpression, filterExpression)));

var negatedName = Framework.Common.Extensions.ExpressionExtensions.GetPropertyName<FacetWidget<T>, bool>(f => f.Negate);
var isCheckedName = Framework.Common.Extensions.ExpressionExtensions.GetPropertyName<FacetViewModel<T>, bool>(f => f.IsChecked);

//get isChecked change event from all items
var itemIsCheckedEvents = Items.Select(
    i => Observable.FromEventPattern<PropertyChangedEventHandler, PropertyChangedEventArgs>
    (h => i.PropertyChanged += h, h => i.PropertyChanged -= h)
    .Where(p => p.EventArgs.PropertyName == isCheckedName));

//and the negate changed event from this
var thisWidgetIsNegatedEvent = new[] {Observable.FromEventPattern<PropertyChangedEventHandler, PropertyChangedEventArgs>
    (h => this.PropertyChanged += h, h => this.PropertyChanged -= h)
    .Where(e => e.EventArgs.PropertyName == negatedName)};

itemIsCheckedEvents.Concat(thisWidgetIsNegatedEvent)
     .Merge()
     .Throttle(TimeSpan.FromMilliseconds(800))
     .Subscribe(e => OnFilterChanged());