From 986c46d0d410bb80a83ac37da0c68c2ad2f390b3 Mon Sep 17 00:00:00 2001
From: Paul DiPietro <pauldipietro@users.noreply.github.com>
Date: Fri, 17 Feb 2017 04:44:14 -0600
Subject: [PATCH] [A] Do not throw error for first param in ScrollTo (#742)

---
 .../Bugzilla41600.cs                               | 51 ++++++++++++++++++++++
 .../Xamarin.Forms.Controls.Issues.Shared.projitems |  1 +
 .../Renderers/ListViewRenderer.cs                  |  3 ++
 3 files changed, 55 insertions(+)
 create mode 100644 Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla41600.cs

diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla41600.cs b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla41600.cs
new file mode 100644
index 0000000..21b3df2
--- /dev/null
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla41600.cs
@@ -0,0 +1,51 @@
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+using System.Collections.Generic;
+
+#if UITEST
+using Xamarin.UITest;
+using NUnit.Framework;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Bugzilla, 41600, "[Android] Invalid item param value for ScrollTo throws an error", PlatformAffected.Android)]
+	public class Bugzilla41600 : TestContentPage
+	{
+		protected override void Init()
+		{
+			var items = new List<string>();
+			for (var i = 0; i <= 30; i++)
+				items.Add(i.ToString());
+
+			var listView = new ListView
+			{
+				ItemsSource = items
+			};
+			Content = new StackLayout
+			{
+				Children =
+				{
+					listView,
+					new Button
+					{
+						Text = "Click for ScrollTo (should do nothing)",
+						Command = new Command(() =>
+						{
+							listView.ScrollTo("Hello", ScrollToPosition.Start, true);
+						})
+					},
+					new Button
+					{
+						Text = "Click for ScrollTo (should go to 15)",
+						Command = new Command(() =>
+						{
+							listView.ScrollTo(items[15], ScrollToPosition.Start, false);
+						})
+					}
+				}
+			};
+		}
+	}
+}
\ No newline at end of file
diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
index 8aa7217..36c7a2b 100644
--- a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
@@ -130,6 +130,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla41415.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla41418.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla41424.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Bugzilla41600.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla41619.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla42069.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla42069_Page.xaml.cs">
diff --git a/Xamarin.Forms.Platform.Android/Renderers/ListViewRenderer.cs b/Xamarin.Forms.Platform.Android/Renderers/ListViewRenderer.cs
index 1054e1e..fa83b25 100644
--- a/Xamarin.Forms.Platform.Android/Renderers/ListViewRenderer.cs
+++ b/Xamarin.Forms.Platform.Android/Renderers/ListViewRenderer.cs
@@ -206,6 +206,9 @@ namespace Xamarin.Forms.Platform.Android
 			else
 			{
 				position = templatedItems.GetGlobalIndexOfItem(scrollArgs.Item);
+				if (position == -1)
+					return;
+
 				cell = templatedItems[position];
 			}
 
-- 
2.7.4