From 1d14364c5f027a08ab789315331917706e275644 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Mon, 25 Nov 2024 16:37:54 -0800
Subject: [PATCH] Hide/show titlebar on modal pages w/ Windows (#26111)

---
 .../ModalNavigationManager.Windows.cs         | 23 ++++++++---
 .../src/Platform/Windows/WindowRootView.cs    | 41 ++++++++-----------
 2 files changed, 34 insertions(+), 30 deletions(-)

diff --git a/src/Controls/src/Core/Platform/ModalNavigationManager/ModalNavigationManager.Windows.cs b/src/Controls/src/Core/Platform/ModalNavigationManager/ModalNavigationManager.Windows.cs
index 5d9405e54e2f..1fbeb11faa49 100644
--- a/src/Controls/src/Core/Platform/ModalNavigationManager/ModalNavigationManager.Windows.cs
+++ b/src/Controls/src/Core/Platform/ModalNavigationManager/ModalNavigationManager.Windows.cs
@@ -104,13 +104,18 @@ void SetCurrent(
 					newPage.Toolbar ??= new Toolbar(newPage);
 					_ = newPage.Toolbar.ToPlatform(modalContext);
 
-					var windowManager = modalContext.GetNavigationRootManager();
-
-					if (windowManager.RootView is WindowRootView wrv)
+					// Hide titlebar on previous page
+					var previousContext = previousPage.FindMauiContext();
+					if (previousContext is not null)
 					{
-						wrv.SetTitleBarBackgroundToTransparent(false);
+						var navRoot = previousContext.GetNavigationRootManager();
+						if (navRoot.RootView is WindowRootView wrv && wrv.AppTitleBarContainer is not null)
+						{
+							wrv.SetTitleBarVisibility(UI.Xaml.Visibility.Collapsed);
+						}
 					}
 
+					var windowManager = modalContext.GetNavigationRootManager();
 					var platform = newPage.ToPlatform(modalContext);
 					_waitingForIncomingPage = platform.OnLoaded(() => completedCallback?.Invoke());
 					windowManager.Connect(platform);
@@ -119,9 +124,17 @@ void SetCurrent(
 				// popping modal
 				else
 				{
-					var windowManager = newPage.FindMauiContext()?.GetNavigationRootManager() ??
+					var context = newPage.FindMauiContext();
+					var windowManager = context?.GetNavigationRootManager() ??
 						throw new InvalidOperationException("Previous Page Has Lost its MauiContext");
 
+					// Toggle the titlebar visibility on the new page
+					var navRoot = context.GetNavigationRootManager();
+					if (navRoot.RootView is WindowRootView wrv && wrv.AppTitleBarContainer is not null)
+					{
+						wrv.SetTitleBarVisibility(UI.Xaml.Visibility.Visible);
+					}
+
 					var platform = newPage.ToPlatform();
 					_waitingForIncomingPage = platform.OnLoaded(() => completedCallback?.Invoke());
 					Container.AddPage(windowManager.RootView);
diff --git a/src/Core/src/Platform/Windows/WindowRootView.cs b/src/Core/src/Platform/Windows/WindowRootView.cs
index 1e12e398b213..7670a08ef7bc 100644
--- a/src/Core/src/Platform/Windows/WindowRootView.cs
+++ b/src/Core/src/Platform/Windows/WindowRootView.cs
@@ -108,8 +108,6 @@ internal FrameworkElement? AppTitleBar
 					_appTitleBar = cp;
 				}
 
-				UpdateAppTitleBarTransparency();
-
 				return _appTitleBar;
 			}
 		}
@@ -477,6 +475,22 @@ internal void SetTitleBar(ITitleBar? titlebar, IMauiContext? mauiContext)
 			}
 		}
 
+		internal void SetTitleBarVisibility(UI.Xaml.Visibility visibility)
+		{
+			// Set default and custom titlebar container visibility
+			if (AppTitleBarContainer is not null)
+			{
+				AppTitleBarContainer.Visibility = visibility;
+			}
+
+			// Set the back/flyout button container visibility
+			if (NavigationViewControl is not null &&
+				NavigationViewControl.ButtonHolderGrid is not null)
+			{
+				NavigationViewControl.ButtonHolderGrid.Visibility = visibility;
+			}
+		}
+
 		private void TitlebarPropChanged_PropertyChanged(object? sender, PropertyChangedEventArgs e)
 		{
 			if (_titleBar is not null && _titleBar.Handler?.MauiContext is not null)
@@ -553,29 +567,6 @@ internal String? WindowTitle
 			set => SetValue(TitleProperty, value);
 		}
 
-		// Once we switch the TitleBar over to using replaceable IViews we won't need this
-		// but for the sake of first just getting us converted over to the new TitleBar
-		// APIs
-		bool _setTitleBarBackgroundToTransparent = true;
-		internal void SetTitleBarBackgroundToTransparent(bool value)
-		{
-			_setTitleBarBackgroundToTransparent = value;
-			if (value)
-			{
-				UpdateAppTitleBarTransparency();
-			}
-			else
-			{
-				_appTitleBar?.RefreshThemeResources();
-			}
-		}
-
-		void UpdateAppTitleBarTransparency()
-		{
-			if (_setTitleBarBackgroundToTransparent && _appTitleBar is Border border)
-				border.Background = null;
-		}
-
 		internal static readonly DependencyProperty WindowTitleBarContentProperty =
 			DependencyProperty.Register(
 				nameof(WindowTitleBarContent),