1 files changed, 112 insertions, 0 deletions
diff --git a/Xamarin.Forms.Core/ObservableList.cs b/Xamarin.Forms.Core/ObservableList.cs
new file mode 100644
index 00000000..82a6c493
--- /dev/null
+++ b/Xamarin.Forms.Core/ObservableList.cs
@@ -0,0 +1,112 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Collections.Specialized;
+using System.Linq;
+
+namespace Xamarin.Forms
+{
+	internal class ObservableList<T> : ObservableCollection<T>
+	{
+		// There's lots of special-casing optimizations that could be done here
+		// but right now this is only being used for tests.
+
+		public void AddRange(IEnumerable<T> range)
+		{
+			if (range == null)
+				throw new ArgumentNullException("range");
+
+			List<T> items = range.ToList();
+			int index = Items.Count;
+			foreach (T item in items)
+				Items.Add(item);
+
+			OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, items, index));
+		}
+
+		public void InsertRange(int index, IEnumerable<T> range)
+		{
+			if (index < 0 || index > Count)
+				throw new ArgumentOutOfRangeException("index");
+			if (range == null)
+				throw new ArgumentNullException("range");
+
+			int originalIndex = index;
+
+			List<T> items = range.ToList();
+			foreach (T item in items)
+				Items.Insert(index++, item);
+
+			OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, items, originalIndex));
+		}
+
+		public void Move(int oldIndex, int newIndex, int count)
+		{
+			if (oldIndex < 0 || oldIndex + count > Count)
+				throw new ArgumentOutOfRangeException("oldIndex");
+			if (newIndex < 0 || newIndex + count > Count)
+				throw new ArgumentOutOfRangeException("newIndex");
+
+			var items = new List<T>(count);
+			for (var i = 0; i < count; i++)
+			{
+				T item = Items[oldIndex];
+				items.Add(item);
+				Items.RemoveAt(oldIndex);
+			}
+
+			int index = newIndex;
+			if (newIndex > oldIndex)
+				index -= items.Count - 1;
+
+			for (var i = 0; i < items.Count; i++)
+				Items.Insert(index + i, items[i]);
+
+			OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Move, items, newIndex, oldIndex));
+		}
+
+		public void RemoveAt(int index, int count)
+		{
+			if (index < 0 || index + count > Count)
+				throw new ArgumentOutOfRangeException("index");
+
+			T[] items = Items.Skip(index).Take(count).ToArray();
+			for (int i = index; i < count; i++)
+				Items.RemoveAt(i);
+
+			OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, items, index));
+		}
+
+		public void RemoveRange(IEnumerable<T> range)
+		{
+			if (range == null)
+				throw new ArgumentNullException("range");
+
+			List<T> items = range.ToList();
+			foreach (T item in items)
+				Items.Remove(item);
+
+			OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, items));
+		}
+
+		public void ReplaceRange(int startIndex, IEnumerable<T> items)
+		{
+			if (items == null)
+				throw new ArgumentNullException("items");
+
+			T[] ritems = items.ToArray();
+
+			if (startIndex < 0 || startIndex + ritems.Length > Count)
+				throw new ArgumentOutOfRangeException("startIndex");
+
+			var oldItems = new T[ritems.Length];
+			for (var i = 0; i < ritems.Length; i++)
+			{
+				oldItems[i] = Items[i + startIndex];
+				Items[i + startIndex] = ritems[i];
+			}
+
+			OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Replace, ritems, oldItems, startIndex));
+		}
+	}
+}
+\ No newline at end of file