From 4ea528643e8c23c8cde47d312665c6fe08701d6d Mon Sep 17 00:00:00 2001
From: adrianknight89 <adrianknight89@outlook.com>
Date: Wed, 28 Dec 2016 17:15:45 -0600
Subject: fix nre when changing content in datepickerselected (#494)

---
 .../Bugzilla38723.cs                               | 58 ++++++++++++++++++++++
 .../Xamarin.Forms.Controls.Issues.Shared.projitems |  1 +
 .../Renderers/PickerRenderer.cs                    |  2 +-
 3 files changed, 60 insertions(+), 1 deletion(-)
 create mode 100644 Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla38723.cs

diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla38723.cs b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla38723.cs
new file mode 100644
index 00000000..2defadec
--- /dev/null
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla38723.cs
@@ -0,0 +1,58 @@
+using System;
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+
+#if UITEST
+using Xamarin.UITest;
+using NUnit.Framework;
+#endif
+
+namespace Xamarin.Forms.Controls
+{
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Bugzilla, 38723, "Update Content in Picker's SelectedIndexChanged event causes NullReferenceException", PlatformAffected.iOS)]
+	public class Bugzilla38723 : TestContentPage // or TestMasterDetailPage, etc ...
+	{
+		Picker _datePicker;
+		Label _dateLabel;
+
+		protected override void Init()
+		{
+			_datePicker = new Picker
+			{
+				//HorizontalOptions = LayoutOptions.FillAndExpand,
+				VerticalOptions = LayoutOptions.Center,
+				Title = "Pick a Date",
+			};
+			_datePicker.SelectedIndexChanged += DatePickerSelected;
+
+			for (var i = 0; i < 7; i++)
+			{
+				_datePicker.Items.Add(DateTime.Now.AddDays(i).ToString("dd, MMM, yyyy(dddd)"));
+			}
+
+			var stackLayout = new StackLayout
+			{
+				Padding = new Thickness(10, 10)
+			};
+
+			_dateLabel = new Label
+			{
+				HorizontalOptions = LayoutOptions.StartAndExpand,
+				VerticalOptions = LayoutOptions.Center,
+				Text = "Placeholder"
+			};
+
+			stackLayout.Children.Add(_datePicker);
+			stackLayout.Children.Add(_dateLabel);
+			// Update current page's UI would cause NullReferenceException
+			Content = stackLayout;
+		}
+
+		void DatePickerSelected(object sender, EventArgs args)
+		{
+			_dateLabel.Text = args.ToString();
+			Content = _dateLabel;
+		}
+	}
+}
\ 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 895bcc9c..53ae50ad 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
@@ -82,6 +82,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla37863.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla37601.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla38105.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Bugzilla38723.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla38827.xaml.cs">
       <DependentUpon>Bugzilla38827.xaml</DependentUpon>
       <SubType>Code</SubType>
diff --git a/Xamarin.Forms.Platform.iOS/Renderers/PickerRenderer.cs b/Xamarin.Forms.Platform.iOS/Renderers/PickerRenderer.cs
index 5a7fa22d..169ac3ed 100644
--- a/Xamarin.Forms.Platform.iOS/Renderers/PickerRenderer.cs
+++ b/Xamarin.Forms.Platform.iOS/Renderers/PickerRenderer.cs
@@ -108,9 +108,9 @@ namespace Xamarin.Forms.Platform.iOS
 			if (Element != null)
 			{
 				var oldText = Control.Text;
-				ElementController.SetValueFromRenderer(Picker.SelectedIndexProperty, s.SelectedIndex);
 				Control.Text = s.SelectedItem;
 				UpdatePickerNativeSize(oldText);
+				ElementController.SetValueFromRenderer(Picker.SelectedIndexProperty, s.SelectedIndex);
 			}
 		}
 
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