Renamed some collection methods.

Added IsEmpty normal property.

ReactiveUI.Routing/RoutingState.cs

@@ -69,7 +69,7 @@ void setupRx()
             if (rxObjectsSetup) return;
 
             NavigateBack = new ReactiveCommand(
-                NavigationStack.CollectionCountChanged.StartWith(_NavigationStack.Count).Select(x => x > 1));
+                NavigationStack.CountChanged.StartWith(_NavigationStack.Count).Select(x => x > 1));
             NavigateBack.Subscribe(_ =>
                 NavigationStack.RemoveAt(NavigationStack.Count - 1));
 
@@ -129,7 +129,7 @@ public static IRoutableViewModel GetCurrentViewModel(this IRoutingState This)
         /// </summary>
         public static IObservable<IRoutableViewModel> ViewModelObservable(this IRoutingState This)
         {
-            return This.NavigationStack.CollectionCountChanged
+            return This.NavigationStack.CountChanged
                 .Select(_ => This.GetCurrentViewModel())
                 .StartWith(This.GetCurrentViewModel());
         }

ReactiveUI.Routing/RxRouting.cs

@@ -125,7 +125,7 @@ public static IDisposable WhenNavigatedTo(this IRoutableViewModel This, Func<IDi
             IDisposable inner = null;
 
             var router = This.HostScreen.Router;
-            return router.NavigationStack.CollectionCountChanged.Subscribe(_ => {
+            return router.NavigationStack.CountChanged.Subscribe(_ => {
                 if (router.GetCurrentViewModel() == This) {
                     if (inner != null)  inner.Dispose();
                     inner = onNavigatedTo();

ReactiveUI.Tests/ReactiveCollectionTest.cs

@@ -24,8 +24,8 @@ public void CollectionCountChangedTest()
             var before_output = new List<int>();
             var output = new List<int>();
 
-            fixture.CollectionCountChanging.Subscribe(before_output.Add);
-            fixture.CollectionCountChanged.Subscribe(output.Add);
+            fixture.CountChanging.Subscribe(before_output.Add);
+            fixture.CountChanged.Subscribe(output.Add);
 
             fixture.Add(10);
             fixture.Add(20);
@@ -47,7 +47,7 @@ public void CollectionCountChangedFiresWhenClearing()
         {
             var items = new ReactiveCollection<object>(new []{new object()});
             bool countChanged = false;
-            items.CollectionCountChanged.Subscribe(_ => {countChanged = true;});
+            items.CountChanged.Subscribe(_ => {countChanged = true;});
 
             items.Clear();
 

ReactiveUI/Interfaces.cs

@@ -148,18 +148,18 @@ public interface IReactiveCollection : IEnumerable, INotifyCollectionChanged
         /// Fires whenever the number of items in a collection has changed,
         /// providing the new Count.
         /// </summary>
-        IObservable<int> CollectionCountChanged { get; }
+        IObservable<int> CountChanged { get; }
 
         /// <summary>
         /// Fires before a collection is about to change, providing the previous
         /// Count.
         /// </summary>
-        IObservable<int> CollectionCountChanging { get; }
+        IObservable<int> CountChanging { get; }
 
         /// <summary>
         /// Fires when a collection becomes or stops being empty.
         /// </summary>
-        IObservable<bool> IsEmpty { get; }
+        IObservable<bool> IsEmptyChanged { get; }
 
         //
         // Change Tracking

ReactiveUI/ReactiveCollection.cs

@@ -97,14 +97,19 @@ void setupRx(IEnumerable<T> initialContents = null, IScheduler scheduler = null,
             // NB: ObservableCollection has a Secret Handshake with WPF where 
             // they fire an INPC notification with the token "Item[]". Emulate 
             // it here
-            CollectionCountChanging.Subscribe(_ => {
+            CountChanging.Subscribe(_ => {
                 if (PropertyChanging != null) PropertyChanging(this, new PropertyChangingEventArgs("Count"));
             });
 
-            CollectionCountChanged.Subscribe(_ => {
+            CountChanged.Subscribe(_ => {
                 if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("Count"));
             });
 
+            IsEmptyChanged.Subscribe(_ =>
+            {
+                if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("IsEmpty"));
+            });
+
             Changing.Subscribe(_ => {
                 if (PropertyChanging != null) PropertyChanging(this, new PropertyChangingEventArgs("Item[]"));
             });
@@ -116,6 +121,11 @@ void setupRx(IEnumerable<T> initialContents = null, IScheduler scheduler = null,
             rxObjectsSetup = true;
         }
 
+        public bool IsEmpty
+        {
+            get { return this.Count == 0; }
+        }
+
 
         /*
          * Collection<T> core methods
@@ -374,15 +384,15 @@ public IDisposable SuppressChangeNotifications()
             }
         }
 
-        public IObservable<int> CollectionCountChanging {
+        public IObservable<int> CountChanging {
             get { return _changing.Select(_ => _inner.Count).DistinctUntilChanged(); }
         }
 
-        public IObservable<int> CollectionCountChanged {
+        public IObservable<int> CountChanged {
             get { return _changed.Select(_ => _inner.Count).DistinctUntilChanged(); }
         }
 
-        public IObservable<bool> IsEmpty {
+        public IObservable<bool> IsEmptyChanged {
             get { return _changed.Select(_ => _inner.Count == 0).DistinctUntilChanged(); }
         }