1 files changed, 178 insertions, 0 deletions
diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla27642.cs b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla27642.cs
new file mode 100644
index 00000000..ec2c203e
--- /dev/null
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla27642.cs
@@ -0,0 +1,178 @@
+using System;
+
+using Xamarin.Forms.CustomAttributes;
+using System.Text;
+
+#if UITEST
+using Xamarin.UITest;
+using NUnit.Framework;
+#endif
+
+namespace Xamarin.Forms.Controls
+{
+	[Preserve (AllMembers = true)]
+	[Issue (IssueTracker.Bugzilla, 27642, "[Windows Phone] Adding a ScrollView control to a ContentView, remove it and re-add it will cause an exception on Windows Phone")]
+	public class Bugzilla27642 : TestContentPage // or TestMasterDetailPage, etc ...
+	{
+		ContentView _mainContent;
+		protected override void Init ()
+		{
+			var rootGrid = new Grid {
+				RowDefinitions = new RowDefinitionCollection
+														  {
+															 new RowDefinition { Height = new GridLength(1, GridUnitType.Star) },
+															 new RowDefinition { Height = new GridLength(1, GridUnitType.Auto) },
+														 },
+			};
+
+
+			_mainContent = new ContentView { Content = new ScrollView { Content = new Label { Text = Description } } };
+			rootGrid.AddChild (_mainContent, 0, 0);
+
+
+			var buttons = new StackLayout { Orientation = StackOrientation.Horizontal };
+
+			var button1A = new Button { Text = "View 1A" };
+			button1A.Clicked += (sender, args) => ShowView (_view1A);
+			buttons.Children.Add (button1A);
+
+			var button1B = new Button { Text = "View 1B" };
+			button1B.Clicked += (sender, args) => ShowView (_view1B);
+			buttons.Children.Add (button1B);
+
+			var button2 = new Button { Text = "View 2" };
+			button2.Clicked += (sender, args) => ShowView (_view2);
+			buttons.Children.Add (button2);
+
+			rootGrid.AddChild (buttons, 0, 1);
+
+
+			Content = rootGrid;
+		}
+
+		const string Description = "A view containing a ScrollView cannot be re-used (same instance, Singleton) \n\n\n"
+								+ "Steps to reproduce: \n\n" + "View1a contains a ScrollView \n"
+								+ "Click: View1A -> View2 -> View1A => Exception\n\n"
+								+ "View1b also contains a ScrollView, but its Content (including ScrollView!) will be re-generated during activation.\n"
+								+ "Click: View1B -> View2 -> View1B => Exception\n\n"
+								+ "View2 doesn't contain a ScrollView and therefore can be called again without problems.\n\n"
+								+ "The Error-Message-View contains a ScrollView, too but will be re-created every time.";
+
+		readonly View1A _view1A = new View1A ();  // always same instance, simulates Singleton from IoC
+		readonly View1B _view1B = new View1B ();  // -"-
+		readonly View2 _view2 = new View2 ();     // -"-
+
+		void ShowView (ExtendedContentView view)
+		{
+			try {
+				view.Activating ();    // implemented only for View1B
+				_mainContent.Content = view;
+			}
+			catch (Exception ex) {
+				_mainContent.Content = new ErrorView (ex);
+			}
+		}
+
+		[Preserve (AllMembers = true)]
+		public class ExtendedContentView : ContentView
+		{
+			public virtual void Activating ()
+			{
+			}
+		}
+	
+		[Preserve (AllMembers = true)]
+		public class View1A : ExtendedContentView
+		{
+			public View1A ()
+			{
+
+				BackgroundColor = Color.Olive;
+				var scrollView = new ScrollView ();
+				var sb = new StringBuilder ();
+				for (var i = 0; i < 100; i++)
+					sb.Append ("View 1a with ScrollView +++ ");
+
+				var label = new Label { Text = sb.ToString (), HorizontalOptions = LayoutOptions.Center, VerticalOptions = LayoutOptions.Center, XAlign = TextAlignment.Center, };
+
+				scrollView.Content = label;
+
+				Content = scrollView;
+
+			}
+
+		}
+
+		[Preserve (AllMembers = true)]
+		public class View1B : ExtendedContentView
+		{
+			public View1B ()
+			{
+				BackgroundColor = Color.Navy;
+			}
+
+			public override void Activating ()
+			{
+				var scrollView = new ScrollView ();
+				var sb = new StringBuilder ();
+				for (var i = 0; i < 50; i++)
+					sb.Append ("View 1b with ScrollView and recreation of content +++++ ");
+
+				var label = new Label { Text = sb.ToString (), HorizontalOptions = LayoutOptions.Center, VerticalOptions = LayoutOptions.Center, XAlign = TextAlignment.Center, };
+
+				scrollView.Content = label;
+
+				Content = scrollView;
+
+			}
+		}
+
+		public class View2 : ExtendedContentView
+		{
+			public View2 ()
+			{
+				BackgroundColor = Color.Teal;
+				Content = new Label { Text = "View 2", HorizontalOptions = LayoutOptions.Center, VerticalOptions = LayoutOptions.Center, XAlign = TextAlignment.Center, };
+			}
+		}
+
+		[Preserve (AllMembers = true)]
+		public class ErrorView : ExtendedContentView
+		{
+			public ErrorView (Exception ex)
+			{
+				BackgroundColor = Color.Maroon;
+				Content = new ScrollView { Content = new Label { Text = ex.ToString () } };
+			}
+		}
+
+	}
+
+	public static class GridExtension
+	{
+		public static void AddChild (this Grid grid, View view, int column, int row, int columnspan = 1, int rowspan = 1)
+		{
+			if (row < 0) {
+				throw new ArgumentOutOfRangeException ("row");
+			}
+			if (column < 0) {
+				throw new ArgumentOutOfRangeException ("column");
+			}
+			if (rowspan <= 0) {
+				throw new ArgumentOutOfRangeException ("rowspan");
+			}
+			if (columnspan <= 0) {
+				throw new ArgumentOutOfRangeException ("columnspan");
+			}
+			if (view == null) {
+				throw new ArgumentNullException ("view");
+			}
+
+			Grid.SetRow (view, row);
+			Grid.SetRowSpan (view, rowspan);
+			Grid.SetColumn (view, column);
+			Grid.SetColumnSpan (view, columnspan);
+			grid.Children.Add (view);
+		}
+	}
+}