Navigationbar BarBackgroundColor is not updating (dotnet#23195)

src/Controls/src/Core/Compatibility/Handlers/NavigationPage/iOS/NavigationRenderer.cs

@@ -474,6 +474,7 @@ void HandlePropertyChanged(object sender, PropertyChangedEventArgs e)
 				e.PropertyName == NavigationPage.BarBackgroundProperty.PropertyName)
 			{
 				UpdateBarBackground();
+				UpdateToolbarItems();
 			}
 			else if (e.PropertyName == NavigationPage.BarTextColorProperty.PropertyName
 				  || e.PropertyName == StatusBarTextColorModeProperty.PropertyName)
@@ -484,6 +485,7 @@ void HandlePropertyChanged(object sender, PropertyChangedEventArgs e)
 			else if (e.PropertyName == VisualElement.BackgroundColorProperty.PropertyName)
 			{
 				UpdateBackgroundColor();
+				UpdateToolbarItems();
 			}
 			else if (e.PropertyName == NavigationPage.CurrentPageProperty.PropertyName)
 			{
@@ -710,6 +712,12 @@ void UpdateBackgroundColor()
 			View.BackgroundColor = color;
 		}
 
+		void UpdateToolbarItems()
+		{
+			var pack = (ParentingViewController)TopViewController;
+			pack?.UpdateToolbarItems();
+		}
+
 		void UpdateBarBackground()
 		{
 			var barBackgroundColor = NavPage.BarBackgroundColor;
@@ -1620,7 +1628,7 @@ void UpdateNavigationBarVisibility(bool animated)
 				}
 			}
 
-			void UpdateToolbarItems()
+			internal void UpdateToolbarItems()
 			{
 				if (NavigationItem.RightBarButtonItems != null)
 				{

src/Controls/src/Core/Element/Element.cs

@@ -587,6 +587,8 @@ protected virtual void OnChildAdded(Element child)
 		{
 			child.SetParent(this);
 
+			child.ApplyBindings();
+
 			ChildAdded?.Invoke(this, new ElementEventArgs(child));
 
 			VisualDiagnostics.OnChildAdded(this, child);

src/Controls/tests/TestCases.HostApp/Issues/Issues23195.xaml

@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<NavigationPage
+    xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+    x:Name="Self"
+    BarBackgroundColor="{AppThemeBinding Light=White,Dark=Black}"
+    BarTextColor="{AppThemeBinding Light=Black,Dark=White}"
+    x:Class="Maui.Controls.Sample.Issues.Issue23195">
+    <x:Arguments>
+        <ContentPage x:Name="contentPage" Title="Content page">
+            <ContentPage.ToolbarItems>
+                <ToolbarItem>
+                    <ToolbarItem.IconImageSource>
+                        <FontImageSource Glyph="&#xf133;"
+                                         Color="{AppThemeBinding Light=Black, Dark=White}"
+                                         FontFamily="FA"/>
+                    </ToolbarItem.IconImageSource>
+                </ToolbarItem>
+            </ContentPage.ToolbarItems>
+            <VerticalStackLayout>
+            <Button Text="Chnage theme" 
+                    AutomationId="button" 
+                    HeightRequest="100" 
+                    Clicked="Button_Clicked"/>
+            <Label Text="Dark theme applied"
+                   IsVisible="{AppThemeBinding Default=False,Dark=True}"           
+                   AutomationId="label"/>
+            </VerticalStackLayout>
+        </ContentPage>
+    </x:Arguments>
+</NavigationPage>

src/Controls/tests/TestCases.HostApp/Issues/Issues23195.xaml.cs

@@ -0,0 +1,18 @@
+namespace Maui.Controls.Sample.Issues
+{
+	[XamlCompilation(XamlCompilationOptions.Compile)]
+	[Issue(IssueTracker.Github, 23195, "NavigationBarColors from NavigationPage not changing on AppTheme changing", PlatformAffected.Android | PlatformAffected.iOS)]
+	public partial class Issue23195 : NavigationPage
+	{
+		public Issue23195()
+		{
+			InitializeComponent();
+			PushAsync(contentPage);
+		}
+
+		public void Button_Clicked(object sender, EventArgs eventArgs)
+		{
+			Application.Current!.UserAppTheme = AppTheme.Dark;
+		}
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue23195.cs

@@ -0,0 +1,27 @@
+#if IOS || ANDROID
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues
+{
+	public class Issue23195 : _IssuesUITest
+	{
+		public override string Issue => "NavigationBarColors from NavigationPage not changing on AppTheme changing";
+
+		public Issue23195(TestDevice device) : base(device)
+		{
+		}
+
+		[Test]
+		[Category(UITestCategories.Page)]
+		public void Issue23195Test()
+		{
+			App.WaitForElement("button");
+			App.Click("button");
+			App.WaitForElement("label");
+			VerifyScreenshot();
+		}
+	}
+}
+#endif

src/Controls/tests/Xaml.UnitTests/Issues/Maui23195.xaml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ContentPage
+    xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+    x:Name="contentPage" 
+    x:Class="Microsoft.Maui.Controls.Xaml.UnitTests.Maui23195">
+    <ContentPage.ToolbarItems>
+        <ToolbarItem>
+            <ToolbarItem.IconImageSource>
+                <FontImageSource Glyph="&#xf133;"
+                                 x:Name="fontImage"
+                                 Color="{AppThemeBinding Light=Black, Dark=White}"/>
+            </ToolbarItem.IconImageSource>
+        </ToolbarItem>
+    </ContentPage.ToolbarItems>
+</ContentPage>

src/Controls/tests/Xaml.UnitTests/Issues/Maui23195.xaml.cs

@@ -0,0 +1,50 @@
+using Microsoft.Maui.ApplicationModel;
+using Microsoft.Maui.Controls.Core.UnitTests;
+using Microsoft.Maui.Dispatching;
+using Microsoft.Maui.Graphics;
+using Microsoft.Maui.UnitTests;
+using NUnit.Framework;
+
+namespace Microsoft.Maui.Controls.Xaml.UnitTests
+{
+	public partial class Maui23195 : ContentPage
+	{
+		public Maui23195()
+		{
+			InitializeComponent();
+		}
+
+		public Maui23195(bool useCompiledXaml)
+		{
+			//this stub will be replaced at compile time
+		}
+
+		[TestFixture]
+		class Test
+		{
+			[SetUp]
+			public void Setup()
+			{
+				Application.SetCurrentApplication(new MockApplication());
+				DispatcherProvider.SetCurrent(new DispatcherProviderStub());
+			}
+
+
+			[TearDown] public void TearDown() => AppInfo.SetCurrent(null);
+
+			[Test]
+			public void FontImageColorShouldChangeOnAppThemeChange([Values(false, true)] bool useCompiledXaml)
+			{
+				var contentPage = new Maui23195(useCompiledXaml);
+				Application.Current.MainPage = contentPage;
+				Assert.True(contentPage.fontImage.Parent is not null);
+
+				Application.Current.UserAppTheme = AppTheme.Light;
+				Assert.AreEqual(contentPage.fontImage.Color, Colors.Black);
+
+				Application.Current.UserAppTheme = AppTheme.Dark;
+				Assert.AreEqual(contentPage.fontImage.Color, Colors.White);
+			}
+		}
+	}
+}