From 1e0b71dbaeab723a41914b9f37d0bbdf4d17d7af Mon Sep 17 00:00:00 2001
From: Mike Mostachetti <mjmostachetti@gmail.com>
Date: Wed, 29 Jul 2020 23:23:16 -0700
Subject: [PATCH 1/4] Always call base ChangeVisualState for checkbox

---
 .../Issue3150.cs                              |  1 +
 .../Issue9106.xaml                            | 30 +++++++++
 .../Issue9106.xaml.cs                         | 65 +++++++++++++++++++
 ...rin.Forms.Controls.Issues.Shared.projitems |  8 +++
 Xamarin.Forms.Core/CheckBox.cs                |  4 +-
 5 files changed, 106 insertions(+), 2 deletions(-)
 create mode 100644 Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9106.xaml
 create mode 100644 Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9106.xaml.cs

diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue3150.cs b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue3150.cs
index 528181ef2df..2208e896839 100644
--- a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue3150.cs
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue3150.cs
@@ -24,6 +24,7 @@ protected override void Init()
 				}
 			};
 
+
 			Button button = null;
 			button = new Button()
 			{
diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9106.xaml b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9106.xaml
new file mode 100644
index 00000000000..a1f47bd541a
--- /dev/null
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9106.xaml
@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<local:TestContentPage xmlns="http://xamarin.com/schemas/2014/forms"
+                       xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+                       xmlns:local="clr-namespace:Xamarin.Forms.Controls"
+                       x:Class="Xamarin.Forms.Controls.Issues.Issue9106">
+    <StackLayout Orientation="Vertical">
+        <Button Text="Toggle IsEnabled" Command="{Binding ToggleCheckboxIsEnabledCommand}"/>
+        <CheckBox x:Name="CheckBoxUnderTest"
+                  IsChecked="{Binding CheckboxIsChecked}"
+                  IsEnabled="{Binding CheckboxIsEnabled}">
+            <VisualStateManager.VisualStateGroups>
+                <VisualStateGroup x:Name="CommonStates">
+                    <VisualState x:Name="Normal">
+                        <VisualState.Setters>
+                            <Setter Property="Color" Value="Green" />
+                        </VisualState.Setters>
+                    </VisualState>
+
+                    <VisualState x:Name="Focused" />
+
+                    <VisualState x:Name="Disabled">
+                        <VisualState.Setters>
+                            <Setter Property="Color" Value="Red" />
+                        </VisualState.Setters>
+                    </VisualState>
+                </VisualStateGroup>
+            </VisualStateManager.VisualStateGroups>
+        </CheckBox>
+    </StackLayout>
+</local:TestContentPage>
\ No newline at end of file
diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9106.xaml.cs b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9106.xaml.cs
new file mode 100644
index 00000000000..e1cf9a61e37
--- /dev/null
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9106.xaml.cs
@@ -0,0 +1,65 @@
+using System;
+using System.Collections.Generic;
+using Xamarin.Forms;
+using System.Threading.Tasks;
+using System.Collections.ObjectModel;
+using System.ComponentModel;
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+using System.Windows.Input;
+#if UITEST
+using Xamarin.UITest;
+using NUnit.Framework;
+using Xamarin.Forms.Core.UITests;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Github, 9106, "[Bug] Checked CheckBox does not update VisualState properly")]
+	public partial class Issue9106 : TestContentPage
+	{
+#if UITEST
+		[Test]
+		[NUnit.Framework.Category(UITestCategories.ManualReview)]
+		public void Issue3798Test()
+		{
+			RunningApp.WaitForElement("listViewSeparatorColor");
+			RunningApp.Screenshot("Green ListView Separator");
+			RunningApp.Tap(q => q.Marked("item1"));
+			RunningApp.Screenshot("Red ListView Separator");
+		}
+#endif
+		public Issue9106()
+		{
+			InitializeComponent();
+		}
+
+
+		protected override void Init()
+		{
+			BindingContext = new Issue9106ViewModel();
+		}
+	}
+
+	[Preserve(AllMembers = true)]
+	public class Issue9106ViewModel : BindableObject
+	{
+		public bool CheckboxIsEnabled { get; set; } 
+		public bool CheckboxIsChecked { get; set; } 
+
+		public Issue9106ViewModel()
+		{
+			CheckboxIsEnabled = false;
+			CheckboxIsChecked = false;
+		}
+
+		public ICommand ToggleCheckboxIsEnabledCommand => new Command(ToggleCheckboxIsEnabled);
+
+		void ToggleCheckboxIsEnabled()
+		{
+			CheckboxIsEnabled = !CheckboxIsEnabled;
+			OnPropertyChanged("CheckboxIsEnabled");
+		}
+	}
+}
\ 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 ae247acd626..00585b2cc39 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
@@ -1444,6 +1444,10 @@
     <Compile Include="$(MSBuildThisFileDirectory)Issue11374.xaml.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue11430.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue11247.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Issue9106.xaml.cs">
+      <DependentUpon>Issue9106.xaml</DependentUpon>
+      <SubType>Code</SubType>
+    </Compile>
   </ItemGroup>
   <ItemGroup>
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Bugzilla22229.xaml">
@@ -1698,6 +1702,10 @@
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Issue11262.xaml">
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>
+    <EmbeddedResource Include="$(MSBuildThisFileDirectory)Issue9106.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
   </ItemGroup>
   <ItemGroup>
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Bugzilla27417Xaml.xaml">
diff --git a/Xamarin.Forms.Core/CheckBox.cs b/Xamarin.Forms.Core/CheckBox.cs
index c4432f88054..ecb8e07292f 100644
--- a/Xamarin.Forms.Core/CheckBox.cs
+++ b/Xamarin.Forms.Core/CheckBox.cs
@@ -34,10 +34,10 @@ public bool IsChecked
 
 		protected internal override void ChangeVisualState()
 		{
+			base.ChangeVisualState();
+
 			if (IsEnabled && IsChecked)
 				VisualStateManager.GoToState(this, IsCheckedVisualState);
-			else
-				base.ChangeVisualState();
 		}
 
 		public event EventHandler<CheckedChangedEventArgs> CheckedChanged;

From 5e528906b5e08d314e033eba401b421dc9ef7db6 Mon Sep 17 00:00:00 2001
From: Mike Mostachetti <mjmostachetti@gmail.com>
Date: Thu, 30 Jul 2020 00:23:38 -0700
Subject: [PATCH 2/4] provide a fallback if the user has not defined IsChecked
 visual state

---
 .../Issue9106.xaml                                  |  1 +
 .../Issue9106.xaml.cs                               | 13 +------------
 Xamarin.Forms.Core/CheckBox.cs                      | 11 ++++++++---
 3 files changed, 10 insertions(+), 15 deletions(-)

diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9106.xaml b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9106.xaml
index a1f47bd541a..8c1460030c2 100644
--- a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9106.xaml
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9106.xaml
@@ -4,6 +4,7 @@
                        xmlns:local="clr-namespace:Xamarin.Forms.Controls"
                        x:Class="Xamarin.Forms.Controls.Issues.Issue9106">
     <StackLayout Orientation="Vertical">
+        <Label Text="Although we did not define a visual state for IsChecked, we return to Normal state when IsChecked is true and we toggle IsEnabled from false to true."/>
         <Button Text="Toggle IsEnabled" Command="{Binding ToggleCheckboxIsEnabledCommand}"/>
         <CheckBox x:Name="CheckBoxUnderTest"
                   IsChecked="{Binding CheckboxIsChecked}"
diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9106.xaml.cs b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9106.xaml.cs
index e1cf9a61e37..f52b7df600b 100644
--- a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9106.xaml.cs
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9106.xaml.cs
@@ -19,17 +19,6 @@ namespace Xamarin.Forms.Controls.Issues
 	[Issue(IssueTracker.Github, 9106, "[Bug] Checked CheckBox does not update VisualState properly")]
 	public partial class Issue9106 : TestContentPage
 	{
-#if UITEST
-		[Test]
-		[NUnit.Framework.Category(UITestCategories.ManualReview)]
-		public void Issue3798Test()
-		{
-			RunningApp.WaitForElement("listViewSeparatorColor");
-			RunningApp.Screenshot("Green ListView Separator");
-			RunningApp.Tap(q => q.Marked("item1"));
-			RunningApp.Screenshot("Red ListView Separator");
-		}
-#endif
 		public Issue9106()
 		{
 			InitializeComponent();
@@ -51,7 +40,7 @@ public class Issue9106ViewModel : BindableObject
 		public Issue9106ViewModel()
 		{
 			CheckboxIsEnabled = false;
-			CheckboxIsChecked = false;
+			CheckboxIsChecked = true;
 		}
 
 		public ICommand ToggleCheckboxIsEnabledCommand => new Command(ToggleCheckboxIsEnabled);
diff --git a/Xamarin.Forms.Core/CheckBox.cs b/Xamarin.Forms.Core/CheckBox.cs
index ecb8e07292f..69d7395aa03 100644
--- a/Xamarin.Forms.Core/CheckBox.cs
+++ b/Xamarin.Forms.Core/CheckBox.cs
@@ -34,10 +34,15 @@ public bool IsChecked
 
 		protected internal override void ChangeVisualState()
 		{
-			base.ChangeVisualState();
-
 			if (IsEnabled && IsChecked)
-				VisualStateManager.GoToState(this, IsCheckedVisualState);
+			{
+				if (!VisualStateManager.GoToState(this, IsCheckedVisualState))
+					VisualStateManager.GoToState(this, "Normal");
+			}
+			else
+			{ 
+				base.ChangeVisualState();
+			}
 		}
 
 		public event EventHandler<CheckedChangedEventArgs> CheckedChanged;

From ef8d2d8cd9c2ba75785a499a86d8287b764350b6 Mon Sep 17 00:00:00 2001
From: Mike Mostachetti <mjmostachetti@gmail.com>
Date: Thu, 30 Jul 2020 10:40:11 -0700
Subject: [PATCH 3/4] provide some fallbacks for when a user doesn't define all
 common states

---
 .../Issue9106.xaml                            |  4 ++-
 Xamarin.Forms.Core/CheckBox.cs                |  5 +--
 Xamarin.Forms.Core/VisualElement.cs           |  3 +-
 Xamarin.Forms.Core/VisualStateManager.cs      | 31 +++++++++++++++++++
 4 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9106.xaml b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9106.xaml
index 8c1460030c2..5cf9aa9b494 100644
--- a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9106.xaml
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9106.xaml
@@ -4,11 +4,13 @@
                        xmlns:local="clr-namespace:Xamarin.Forms.Controls"
                        x:Class="Xamarin.Forms.Controls.Issues.Issue9106">
     <StackLayout Orientation="Vertical">
-        <Label Text="Although we did not define a visual state for IsChecked, we return to Normal state when IsChecked is true and we toggle IsEnabled from false to true."/>
+        <Label Text="If the user forgets to assign IsChecked or Normal for a visual state group but did define Disabled, the Visual State Manager should remove the Disabled Setters when trying to return to a Normal State."/>
         <Button Text="Toggle IsEnabled" Command="{Binding ToggleCheckboxIsEnabledCommand}"/>
         <CheckBox x:Name="CheckBoxUnderTest"
                   IsChecked="{Binding CheckboxIsChecked}"
                   IsEnabled="{Binding CheckboxIsEnabled}">
+
+            <!--Try different combinations of setting visual states-->
             <VisualStateManager.VisualStateGroups>
                 <VisualStateGroup x:Name="CommonStates">
                     <VisualState x:Name="Normal">
diff --git a/Xamarin.Forms.Core/CheckBox.cs b/Xamarin.Forms.Core/CheckBox.cs
index 69d7395aa03..ebc01fd7399 100644
--- a/Xamarin.Forms.Core/CheckBox.cs
+++ b/Xamarin.Forms.Core/CheckBox.cs
@@ -37,10 +37,11 @@ protected internal override void ChangeVisualState()
 			if (IsEnabled && IsChecked)
 			{
 				if (!VisualStateManager.GoToState(this, IsCheckedVisualState))
-					VisualStateManager.GoToState(this, "Normal");
+					if(!VisualStateManager.GoToState(this, VisualStateManager.CommonStates.Normal))
+						VisualStateManager.ResetCommonStatesGroupSetters(this);
 			}
 			else
-			{ 
+			{
 				base.ChangeVisualState();
 			}
 		}
diff --git a/Xamarin.Forms.Core/VisualElement.cs b/Xamarin.Forms.Core/VisualElement.cs
index 42b6e00017c..5c11b103ebe 100644
--- a/Xamarin.Forms.Core/VisualElement.cs
+++ b/Xamarin.Forms.Core/VisualElement.cs
@@ -966,7 +966,8 @@ protected internal virtual void ChangeVisualState()
 			}
 			else
 			{
-				VisualStateManager.GoToState(this, VisualStateManager.CommonStates.Normal);
+				if(!VisualStateManager.GoToState(this, VisualStateManager.CommonStates.Normal))
+					VisualStateManager.ResetCommonStatesGroupSetters(this);
 			}
 		}
 
diff --git a/Xamarin.Forms.Core/VisualStateManager.cs b/Xamarin.Forms.Core/VisualStateManager.cs
index 4014072868f..6223c83bb98 100644
--- a/Xamarin.Forms.Core/VisualStateManager.cs
+++ b/Xamarin.Forms.Core/VisualStateManager.cs
@@ -17,6 +17,8 @@ public class CommonStates
 			public const string Selected = "Selected";
 		}
 
+		public const string CommonStatesGroupName = "CommonStates";
+
 		public static readonly BindableProperty VisualStateGroupsProperty =
 			BindableProperty.CreateAttached("VisualStateGroups", typeof(VisualStateGroupList), typeof(VisualElement),
 				defaultValue: null, propertyChanged: VisualStateGroupsPropertyChanged,
@@ -48,6 +50,35 @@ public static void SetVisualStateGroups(VisualElement visualElement, VisualState
 			visualElement.SetValue(VisualStateGroupsProperty, value);
 		}
 
+		// Use this as a fallback if the user did not define all the common states and got into an undesireable state
+		public static bool ResetCommonStatesGroupSetters(VisualElement visualElement)
+		{
+			if (!visualElement.HasVisualStateGroups())
+			{
+				return false;
+			}
+
+			var groups = (IList<VisualStateGroup>)visualElement.GetValue(VisualStateGroupsProperty);
+
+			foreach (VisualStateGroup group in groups)
+			{
+				if (group.Name == CommonStatesGroupName)
+				{
+					if (group.CurrentState != null)
+					{
+						foreach (Setter setter in group.CurrentState.Setters)
+						{
+							setter.UnApply(visualElement);
+						}
+						group.CurrentState = null;
+						return true;
+					}
+				}
+			}
+
+			return false;
+		}
+
 		public static bool GoToState(VisualElement visualElement, string name)
 		{
 			if (!visualElement.HasVisualStateGroups())

From c15fdb5751a3e154d947ea9b8d3ecbc69ac4ed05 Mon Sep 17 00:00:00 2001
From: Mike Mostachetti <mjmostachetti@gmail.com>
Date: Thu, 30 Jul 2020 10:50:36 -0700
Subject: [PATCH 4/4] remove newline

---
 .../Xamarin.Forms.Controls.Issues.Shared/Issue3150.cs            | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue3150.cs b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue3150.cs
index 2208e896839..528181ef2df 100644
--- a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue3150.cs
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue3150.cs
@@ -24,7 +24,6 @@ protected override void Init()
 				}
 			};
 
-
 			Button button = null;
 			button = new Button()
 			{