[Code] ToStream utils

billy1arm · Nov 10, 2021 · 62b0ee3 · 62b0ee3
1 parent 63f3c9d
commit 62b0ee3
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Showing 2 changed files with 19 additions and 9 deletions.
diff --git a/WDE.MVVM/Observable/Functional/ObservableCollectionStream.cs b/WDE.MVVM/Observable/Functional/ObservableCollectionStream.cs
@@ -10,21 +10,23 @@ public class ObservableCollectionStream<T> : IObservable<CollectionEvent<T>>
         private readonly IEnumerable<T> initial;
         private readonly INotifyCollectionChanged notifyCollectionChanged;
         private readonly bool onRemoveOnDispose;
+        private readonly bool includeInitial;
 
-        public ObservableCollectionStream(IEnumerable<T> initial, INotifyCollectionChanged notifyCollectionChanged, bool onRemoveOnDispose)
+        public ObservableCollectionStream(IEnumerable<T> initial, INotifyCollectionChanged notifyCollectionChanged, bool onRemoveOnDispose, bool includeInitial)
         {
             this.initial = initial;
             this.notifyCollectionChanged = notifyCollectionChanged;
             this.onRemoveOnDispose = onRemoveOnDispose;
+            this.includeInitial = includeInitial;
         }
 
-        public ObservableCollectionStream(ObservableCollection<T> collection, bool onRemoveOnDispose) : this(collection, collection, onRemoveOnDispose)
+        public ObservableCollectionStream(ObservableCollection<T> collection, bool onRemoveOnDispose, bool includeInitial) : this(collection, collection, onRemoveOnDispose, includeInitial)
         {
         }
 
         public IDisposable Subscribe(IObserver<CollectionEvent<T>> observer)
         {
-            return new Subscription(initial, notifyCollectionChanged, observer, onRemoveOnDispose);
+            return new Subscription(initial, notifyCollectionChanged, observer, onRemoveOnDispose, includeInitial);
         }
 
         private class Subscription : IDisposable
@@ -35,7 +37,7 @@ private class Subscription : IDisposable
             private readonly bool removeOnDispose;
 
             public Subscription(IEnumerable<T> initial, INotifyCollectionChanged changed,
-                IObserver<CollectionEvent<T>> observer, bool removeOnDispose)
+                IObserver<CollectionEvent<T>> observer, bool removeOnDispose, bool includeInitial)
             {
                 this.initial = initial;
                 notifyCollectionChanged = changed;
@@ -44,10 +46,13 @@ public Subscription(IEnumerable<T> initial, INotifyCollectionChanged changed,
                 this.removeOnDispose = removeOnDispose;
                 changed.CollectionChanged += CollectionOnCollectionChanged;
 
-                int index = 0;
-                foreach (var t in initial)
+                if (includeInitial)
                 {
-                    observer.OnNext(new CollectionEvent<T>(CollectionEventType.Add, t, index++));   
+                    int index = 0;
+                    foreach (var t in initial)
+                    {
+                        observer.OnNext(new CollectionEvent<T>(CollectionEventType.Add, t, index++));   
+                    }   
                 }
             }
 

diff --git a/WDE.MVVM/Observable/FunctionalExtensions.cs b/WDE.MVVM/Observable/FunctionalExtensions.cs
@@ -26,9 +26,14 @@ public static IObservable<int> ToCountChangedObservable<T>(this ObservableCollec
             return collection.ToObservable(o => o.Count);
         }
 
+        public static IObservable<CollectionEvent<T>> ToStreamForChanges<T>(this ObservableCollection<T> collection)
+        {
+            return new ObservableCollectionStream<T>(collection, false, false);
+        }
+
         public static IObservable<CollectionEvent<T>> ToStream<T>(this ObservableCollection<T> collection, bool onRemoveOnDispose)
         {
-            return new ObservableCollectionStream<T>(collection, onRemoveOnDispose);
+            return new ObservableCollectionStream<T>(collection, onRemoveOnDispose, true);
         }
 
         public static System.IDisposable DisposeOnRemove<T>(this ObservableCollection<T> collection, Func<bool> shouldDispose) where T : System.IDisposable
@@ -97,7 +102,7 @@ public static System.IDisposable ToStreamForEachValue<T>(this ObservableCollecti
 
         public static IObservable<CollectionEvent<T>> ToStream<T>(this INotifyCollectionChanged collection, IEnumerable<T> initial)
         {
-            return new ObservableCollectionStream<T>(initial, collection, false);
+            return new ObservableCollectionStream<T>(initial, collection, false, true);
         }
 
         public static void RemoveAll<T>(this ObservableCollection<T> collection)