Added RaiseChangeNotificationEvents constructor for Replace notificat…

…ions. Updated tests.
jamesmontemagno · Mar 18, 2021 · 6567ab5 · 6567ab5
1 parent 70529f5
commit 6567ab5
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Showing 2 changed files with 22 additions and 8 deletions.
diff --git a/MvvmHelpers.UnitTests/ObservableRangeTests.cs b/MvvmHelpers.UnitTests/ObservableRangeTests.cs
@@ -57,11 +57,8 @@ public void ReplaceRange()
 			collection.CollectionChanged += (s, e) =>
 			{
 				Assert.AreEqual(e.Action,
-								NotifyCollectionChangedAction.Reset,
-								"ReplaceRange didn't use Remove like requested.");
-
-				Assert.IsNull(e.OldItems, "OldItems should be null.");
-				Assert.IsNull(e.NewItems, "NewItems should be null.");
+								NotifyCollectionChangedAction.Replace,
+								"ReplaceRange didn't raised Replace like requested.");
 
 				Assert.AreEqual(collection.Count, toAdd.Length, "Lengths are not the same");
 
@@ -83,6 +80,10 @@ public void ReplaceRange_on_non_empty_collection_should_always_raise_collection_
 
 			collection.CollectionChanged += (s, e) =>
 			{
+				Assert.AreEqual(e.Action,
+								NotifyCollectionChangedAction.Reset,
+								"ReplaceRange didn't raised Reset like requested.");
+
 				eventRaised = true;
 			};
 

diff --git a/MvvmHelpers/ObservableRangeCollection.cs b/MvvmHelpers/ObservableRangeCollection.cs
@@ -3,7 +3,7 @@
 using System.Collections.ObjectModel;
 using System.Collections.Specialized;
 using System.ComponentModel;
-
+using System.Linq;
 
 namespace MvvmHelpers
 {
@@ -128,6 +128,8 @@ public void ReplaceRange(IEnumerable<T> collection)
 
 			var previouslyEmpty = Items.Count == 0;
 
+			var oldItems = new List<T>(Items);
+
 			Items.Clear();
 
 			AddArrangeCore(collection);
@@ -137,7 +139,10 @@ public void ReplaceRange(IEnumerable<T> collection)
 			if (previouslyEmpty && currentlyEmpty)
 				return;
 
-			RaiseChangeNotificationEvents(action: currentlyEmpty ? NotifyCollectionChangedAction.Reset : NotifyCollectionChangedAction.Replace);
+			if (currentlyEmpty)
+				RaiseChangeNotificationEvents(action: NotifyCollectionChangedAction.Reset);
+			else
+				RaiseChangeNotificationEvents(action: NotifyCollectionChangedAction.Replace, oldItems.ToList(), collection.ToList());
 		}
 
 		private bool AddArrangeCore(IEnumerable<T> collection)
@@ -151,7 +156,7 @@ private bool AddArrangeCore(IEnumerable<T> collection)
 			return itemAdded;
 		}
 
-        private void RaiseChangeNotificationEvents(NotifyCollectionChangedAction action, List<T>? changedItems = null, int startingIndex = -1)
+		private void RaiseChangeNotificationEvents(NotifyCollectionChangedAction action, List<T>? changedItems = null, int startingIndex = -1)
         {
             OnPropertyChanged(new PropertyChangedEventArgs(nameof(Count)));
             OnPropertyChanged(new PropertyChangedEventArgs("Item[]"));
@@ -161,5 +166,13 @@ private void RaiseChangeNotificationEvents(NotifyCollectionChangedAction action,
             else
                 OnCollectionChanged(new NotifyCollectionChangedEventArgs(action, changedItems: changedItems, startingIndex: startingIndex));
         }
+
+		private void RaiseChangeNotificationEvents(NotifyCollectionChangedAction action, List<T>? newItems, List<T>? oldItems)
+		{
+			OnPropertyChanged(new PropertyChangedEventArgs(nameof(Count)));
+			OnPropertyChanged(new PropertyChangedEventArgs("Item[]"));
+
+			OnCollectionChanged(new NotifyCollectionChangedEventArgs(action, newItems, oldItems));
+		}
 	}
 }