Including file for testing issue 9451 (#11567)

Co-authored-by: Rui Marinho <[email protected]>
Co-authored-by: Samantha Houts <[email protected]>
fixes #9451

Author: 3 people

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9451.cs

@@ -0,0 +1,55 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using Xamarin.Forms.Internals;
+using Xamarin.Forms.CustomAttributes;
+using System.ComponentModel;
+using System.Threading.Tasks;
+
+namespace Xamarin.Forms.Controls.Issues
+{
+	[Issue(IssueTracker.Github, 9451,
+		"[Bug] RelativeLayout Constraint can not go back to zero", PlatformAffected.All)]
+	public class Issue9451 : TestContentPage
+	{
+		public StackLayout StackLayout { get; set; }
+		public Button TriggerButton { get; set; }
+
+		protected override void Init()
+		{
+			var relativeLayout = new RelativeLayout() { WidthRequest = 400, HeightRequest = 400 };
+			StackLayout = new StackLayout() { BackgroundColor = Color.Red };
+
+			TriggerButton = new Button() { Text = "Set View Width To Zero" };
+
+			StackLayout.Children.Add(TriggerButton);
+
+			relativeLayout.Children.Add(StackLayout,
+				Xamarin.Forms.Constraint.Constant(0),
+				Xamarin.Forms.Constraint.Constant(0),
+				Xamarin.Forms.Constraint.RelativeToParent(x => x.Width / 2),
+				Xamarin.Forms.Constraint.RelativeToParent(y => y.Height));
+
+			Content = relativeLayout;
+		}
+
+		protected override void OnAppearing()
+		{
+			base.OnAppearing();
+
+			TriggerButton.Clicked += Button_Clicked;
+		}
+
+		protected override void OnDisappearing()
+		{
+			base.OnDisappearing();
+
+			TriggerButton.Clicked -= Button_Clicked;
+		}
+
+		private void Button_Clicked(object sender, EventArgs e)
+		{
+			RelativeLayout.SetWidthConstraint(StackLayout, Xamarin.Forms.Constraint.Constant(0.0));
+		}
+	}
+}

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems

@@ -1440,6 +1440,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Issue11291.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue11244.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue11272.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Issue9451.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue11374.xaml.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue11430.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue11247.cs" />