Added new OnCollectionChanged overloads to reduce need for additional…

… if checks.
dotnet · Mar 11, 2019 · bf4b07b · bf4b07b
1 parent 91cf013
commit bf4b07b
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Showing 2 changed files with 20 additions and 18 deletions.
diff --git a/src/System.ObjectModel/src/System/Collections/ObjectModel/ObservableCollection.cs b/src/System.ObjectModel/src/System/Collections/ObjectModel/ObservableCollection.cs
@@ -218,7 +218,7 @@ protected override void ReplaceItemsRange(int index, int count, IEnumerable<T> c
 
             OnCountPropertyChanged();
             OnIndexerPropertyChanged();
-            OnCollectionChanged(NotifyCollectionChangedAction.Replace, itemsToReplace, collection, index);
+            OnCollectionChanged(NotifyCollectionChangedAction.Replace, itemsToReplace, (IList)collection, index);
         }
 
 
@@ -397,14 +397,15 @@ protected void CheckReentrancy()
         /// </summary>
         private void OnCollectionChanged(NotifyCollectionChangedAction action, object item, int index)
         {
-            if (item is IList)
-            {
-                OnCollectionChanged(new NotifyCollectionChangedEventArgs(action, (IList)item, index));
-            }
-            else
-            {
-                OnCollectionChanged(new NotifyCollectionChangedEventArgs(action, item, index));
-            }
+            OnCollectionChanged(new NotifyCollectionChangedEventArgs(action, item, index));
+        }
+
+        /// <summary>
+        /// Helper to raise CollectionChanged event to any listeners
+        /// </summary>
+        private void OnCollectionChanged(NotifyCollectionChangedAction action, IList items, int index)
+        {
+            OnCollectionChanged(new NotifyCollectionChangedEventArgs(action, items, index));
         }
 
         /// <summary>
@@ -420,14 +421,15 @@ private void OnCollectionChanged(NotifyCollectionChangedAction action, object it
         /// </summary>
         private void OnCollectionChanged(NotifyCollectionChangedAction action, object oldItem, object newItem, int index)
         {
-            if (oldItem is IList && newItem is IList)
-            {
-                OnCollectionChanged(new NotifyCollectionChangedEventArgs(action, (IList)oldItem, (IList)newItem, index));
-            }
-            else
-            {
-                OnCollectionChanged(new NotifyCollectionChangedEventArgs(action, newItem, oldItem, index));
-            }
+            OnCollectionChanged(new NotifyCollectionChangedEventArgs(action, newItem, oldItem, index));
+        }
+
+        /// <summary>
+        /// Helper to raise CollectionChanged event to any listeners
+        /// </summary>
+        private void OnCollectionChanged(NotifyCollectionChangedAction action, IList oldItems, IList newItems, int index)
+        {
+            OnCollectionChanged(new NotifyCollectionChangedEventArgs(action, newItems, oldItems, index));
         }
 
         /// <summary>

diff --git a/src/System.ObjectModel/tests/ObservableCollection/ObservableCollection_MethodsTest.cs b/src/System.ObjectModel/tests/ObservableCollection/ObservableCollection_MethodsTest.cs
@@ -690,7 +690,7 @@ public static void RemoveRange_NotifyCollectionChanged_EventArgs_IndexOfZero_Tes
         }
 
         [Fact]
-        public static void RemoveRange_NotifyCollectionChanged_EventArgs_IndexMiddle_Test()
+        public static void RemoveRange_NotifyCollectionChanged_EventArgs_IndexMiddle_Test() 
         {
             int[] initialData = new int[] { 1, 2, 3, 4, 5, 6, 7, 8 };
             int[] actualDataRemoved = new int[0];