From 88bc6a80ceba8380ee8af104d74a47048add3358 Mon Sep 17 00:00:00 2001
From: Shane Neuville <shneuvil@microsoft.com>
Date: Wed, 11 Sep 2019 10:28:21 -0600
Subject: [PATCH] move await to Begin Invoke and check for disposed (#7192)

---
 .../Extensions/NSObjectExtensions.cs                     | 16 ++++++++++++++++
 Xamarin.Forms.Platform.iOS/Renderers/ListViewRenderer.cs | 14 ++++++++------
 .../Xamarin.Forms.Platform.iOS.csproj                    |  1 +
 3 files changed, 25 insertions(+), 6 deletions(-)
 create mode 100644 Xamarin.Forms.Platform.iOS/Extensions/NSObjectExtensions.cs

diff --git a/Xamarin.Forms.Platform.iOS/Extensions/NSObjectExtensions.cs b/Xamarin.Forms.Platform.iOS/Extensions/NSObjectExtensions.cs
new file mode 100644
index 0000000..8eb1d30
--- /dev/null
+++ b/Xamarin.Forms.Platform.iOS/Extensions/NSObjectExtensions.cs
@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+using Foundation;
+using UIKit;
+
+namespace Xamarin.Forms.Platform.iOS
+{
+	internal static class NSObjectExtensions
+	{
+		public static void QueueForLater(this NSObject nsObject, Action action) =>
+			nsObject.BeginInvokeOnMainThread(action);
+	}
+}
\ No newline at end of file
diff --git a/Xamarin.Forms.Platform.iOS/Renderers/ListViewRenderer.cs b/Xamarin.Forms.Platform.iOS/Renderers/ListViewRenderer.cs
index 5aa6d64..0a8dba5 100644
--- a/Xamarin.Forms.Platform.iOS/Renderers/ListViewRenderer.cs
+++ b/Xamarin.Forms.Platform.iOS/Renderers/ListViewRenderer.cs
@@ -360,7 +360,7 @@ namespace Xamarin.Forms.Platform.iOS
 			Control.TableHeaderView = _headerRenderer.NativeView;
 		}
 
-		async void OnScrollToRequested(object sender, ScrollToRequestedEventArgs e)
+		void OnScrollToRequested(object sender, ScrollToRequestedEventArgs e)
 		{
 			if (Superview == null)
 			{
@@ -386,15 +386,17 @@ namespace Xamarin.Forms.Platform.iOS
 					Control.Layer.RemoveAllAnimations();
 					//iOS11 hack
 					if (Forms.IsiOS11OrNewer)
-					{
-						await Task.Delay(1);
-					}
-					Control.ScrollToRow(NSIndexPath.FromRowSection(index, 0), position, e.ShouldAnimate);
+						this.QueueForLater(() =>
+						{
+							if (Control != null && !_disposed)
+								Control.ScrollToRow(NSIndexPath.FromRowSection(index, 0), position, e.ShouldAnimate);
+						});
+					else
+						Control.ScrollToRow(NSIndexPath.FromRowSection(index, 0), position, e.ShouldAnimate);
 				}
 			}
 		}
 
-
 		void UpdateFooter()
 		{
 			var footer = ListView.FooterElement;
diff --git a/Xamarin.Forms.Platform.iOS/Xamarin.Forms.Platform.iOS.csproj b/Xamarin.Forms.Platform.iOS/Xamarin.Forms.Platform.iOS.csproj
index f9937cb..703645f 100644
--- a/Xamarin.Forms.Platform.iOS/Xamarin.Forms.Platform.iOS.csproj
+++ b/Xamarin.Forms.Platform.iOS/Xamarin.Forms.Platform.iOS.csproj
@@ -147,6 +147,7 @@
     <Compile Include="ExportRendererAttribute.cs" />
     <Compile Include="Extensions\ArrayExtensions.cs" />
     <Compile Include="Extensions\FlowDirectionExtensions.cs" />
+    <Compile Include="Extensions\NSObjectExtensions.cs" />
     <Compile Include="Extensions\PlatformConfigurationExtensions.cs" />
     <Compile Include="Extensions\LabelExtensions.cs" />
     <Compile Include="Extensions\VisualElementExtensions.cs" />
-- 
2.7.4