From 496fae20e55995017faf8f6f5672c507dc45fd15 Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Tue, 29 Oct 2019 14:59:47 +0100
Subject: [PATCH] Ensure Items are synchronised with Presenter.

Ensure that the `ItemsControl`'s presenter is notified of an `Items` change at the appropriate time.
---
 src/Avalonia.Controls/ItemsControl.cs               | 7 ++++++-
 src/Avalonia.Controls/Presenters/IItemsPresenter.cs | 3 +++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/Avalonia.Controls/ItemsControl.cs b/src/Avalonia.Controls/ItemsControl.cs
index b93346792d..1203792559 100644
--- a/src/Avalonia.Controls/ItemsControl.cs
+++ b/src/Avalonia.Controls/ItemsControl.cs
@@ -356,10 +356,15 @@ namespace Avalonia.Controls
             var oldValue = e.OldValue as IEnumerable;
             var newValue = e.NewValue as IEnumerable;
 
-            Presenter?.ItemsChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
             UpdateItemCount();
             RemoveControlItemsFromLogicalChildren(oldValue);
             AddControlItemsToLogicalChildren(newValue);
+
+            if (Presenter != null)
+            {
+                Presenter.Items = newValue;
+            }
+
             SubscribeToItems(newValue);
         }
 
diff --git a/src/Avalonia.Controls/Presenters/IItemsPresenter.cs b/src/Avalonia.Controls/Presenters/IItemsPresenter.cs
index 21a03402a0..c4acf1ebef 100644
--- a/src/Avalonia.Controls/Presenters/IItemsPresenter.cs
+++ b/src/Avalonia.Controls/Presenters/IItemsPresenter.cs
@@ -1,12 +1,15 @@
 // Copyright (c) The Avalonia Project. All rights reserved.
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
+using System.Collections;
 using System.Collections.Specialized;
 
 namespace Avalonia.Controls.Presenters
 {
     public interface IItemsPresenter : IPresenter
     {
+        IEnumerable Items { get; set; }
+
         IPanel Panel { get; }
 
         void ItemsChanged(NotifyCollectionChangedEventArgs e);