From 2337da31b1367b57c61ff70b1489f7817d31be6b Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Fri, 7 Aug 2020 15:17:18 +0200
Subject: [PATCH] Add null check for scroller.

---
 src/Avalonia.Controls/Repeater/ViewportManager.cs | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/Avalonia.Controls/Repeater/ViewportManager.cs b/src/Avalonia.Controls/Repeater/ViewportManager.cs
index 796ae8616d..bdb0fa3270 100644
--- a/src/Avalonia.Controls/Repeater/ViewportManager.cs
+++ b/src/Avalonia.Controls/Repeater/ViewportManager.cs
@@ -350,11 +350,14 @@ namespace Avalonia.Controls
                 }
 
                 // Make sure that only the target child can be the anchor during the bring into view operation.
-                foreach (var child in _owner.Children)
+                if (_scroller is object)
                 {
-                    if (child != targetChild)
+                    foreach (var child in _owner.Children)
                     {
-                        _scroller.UnregisterAnchorCandidate(child);
+                        if (child != targetChild)
+                        {
+                            _scroller.UnregisterAnchorCandidate(child);
+                        }
                     }
                 }