One app per process, one logic per window, INIT THE XAML ISLAND BEFORE any xaml

itsworking.gif

dep/nuget/packages.config

@@ -2,7 +2,6 @@
 <!-- The packages.config acts as the global version for all of the NuGet packages contained within. -->
 <packages>
   <!-- Native packages -->
-  <package id="Microsoft.Toolkit.Win32.UI.XamlApplication" version="6.1.3" targetFramework="native" />
   <package id="Microsoft.Internal.PGO-Helpers.Cpp" version="0.2.34" targetFramework="native" />
   <package id="Microsoft.Taef" version="10.60.210621002" targetFramework="native" />
   <package id="Microsoft.Windows.CppWinRT" version="2.0.210825.3" targetFramework="native" />

scratch/ScratchIslandApp/Package/Package.wapproj

@@ -136,12 +136,12 @@
   <!-- **END VC LIBS HACK** -->
 
   <!-- This is required to get the package dependency in the AppXManifest. -->
-  <Import Project="..\..\..\packages\Microsoft.UI.Xaml.2.7.3\build\native\Microsoft.UI.Xaml.targets" Condition="Exists('..\..\..\packages\Microsoft.UI.Xaml.2.7.3\build\native\Microsoft.UI.Xaml.targets')" />
+  <Import Project="..\..\..\packages\Microsoft.UI.Xaml.$(TerminalMUXVersion)\build\native\Microsoft.UI.Xaml.targets" Condition="Exists('..\..\..\packages\Microsoft.UI.Xaml.$(TerminalMUXVersion)\build\native\Microsoft.UI.Xaml.targets')" />
   <Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
     <PropertyGroup>
       <ErrorText>This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
     </PropertyGroup>
-    <Error Condition="!Exists('..\..\..\packages\Microsoft.UI.Xaml.2.7.3\build\native\Microsoft.UI.Xaml.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\..\..\packages\Microsoft.UI.Xaml.2.7.3\build\native\Microsoft.UI.Xaml.targets'))" />
+    <Error Condition="!Exists('..\..\..\packages\Microsoft.UI.Xaml.$(TerminalMUXVersion)\build\native\Microsoft.UI.Xaml.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\..\..\packages\Microsoft.UI.Xaml.$(TerminalMUXVersion)\build\native\Microsoft.UI.Xaml.targets'))" />
   </Target>
 
 

scratch/ScratchIslandApp/SampleApp/App.cpp

@@ -12,19 +12,12 @@ using namespace winrt::Windows::UI::Xaml;
 using namespace winrt::Windows::UI::Xaml::Controls;
 using namespace winrt::Windows::UI::Xaml::Navigation;
 
+namespace xaml = ::winrt::Windows::UI::Xaml;
+
 namespace winrt::SampleApp::implementation
 {
     App::App()
     {
-        // This is the same trick that Initialize() is about to use to figure out whether we're coming
-        // from a UWP context or from a Win32 context
-        // See https://github.com/windows-toolkit/Microsoft.Toolkit.Win32/blob/52611c57d89554f357f281d0c79036426a7d9257/Microsoft.Toolkit.Win32.UI.XamlApplication/XamlApplication.cpp#L42
-        const auto dispatcherQueue = ::winrt::Windows::System::DispatcherQueue::GetForCurrentThread();
-        if (dispatcherQueue)
-        {
-            _isUwp = true;
-        }
-
         Initialize();
 
         // Disable XAML's automatic backplating of text when in High Contrast
@@ -33,10 +26,47 @@ namespace winrt::SampleApp::implementation
         HighContrastAdjustment(::winrt::Windows::UI::Xaml::ApplicationHighContrastAdjustment::None);
     }
 
+    void App::Initialize()
+    {
+        const auto dispatcherQueue = winrt::Windows::System::DispatcherQueue::GetForCurrentThread();
+        if (!dispatcherQueue)
+        {
+            _windowsXamlManager = xaml::Hosting::WindowsXamlManager::InitializeForCurrentThread();
+        }
+        else
+        {
+            _isUwp = true;
+        }
+    }
+
+    void App::Close()
+    {
+        if (_bIsClosed)
+        {
+            return;
+        }
+
+        _bIsClosed = true;
+
+        if (_windowsXamlManager)
+        {
+            _windowsXamlManager.Close();
+        }
+        _windowsXamlManager = nullptr;
+
+        Exit();
+        {
+            MSG msg = {};
+            while (PeekMessageW(&msg, nullptr, 0, 0, PM_REMOVE))
+            {
+                ::DispatchMessageW(&msg);
+            }
+        }
+    }
+
     SampleAppLogic App::Logic()
     {
-        static SampleAppLogic logic;
-        return logic;
+        return nullptr;
     }
 
     /// <summary>

scratch/ScratchIslandApp/SampleApp/App.h

@@ -12,12 +12,22 @@ namespace winrt::SampleApp::implementation
     {
     public:
         App();
+        void Initialize();
+        void Close();
         void OnLaunched(Windows::ApplicationModel::Activation::LaunchActivatedEventArgs const&);
 
+        bool IsDisposed() const
+        {
+            return _bIsClosed;
+        }
+
         SampleApp::SampleAppLogic Logic();
 
     private:
         bool _isUwp = false;
+        winrt::Windows::UI::Xaml::Hosting::WindowsXamlManager _windowsXamlManager = nullptr;
+        winrt::Windows::Foundation::Collections::IVector<winrt::Windows::UI::Xaml::Markup::IXamlMetadataProvider> _providers = winrt::single_threaded_vector<Windows::UI::Xaml::Markup::IXamlMetadataProvider>();
+        bool _bIsClosed = false;
     };
 }
 

scratch/ScratchIslandApp/SampleApp/App.idl

@@ -7,10 +7,12 @@ namespace SampleApp
 {
     // ADD ARBITRARY APP LOGIC TO SampleAppLogic.idl, NOT HERE.
     // This is for XAML platform setup only.
-    [default_interface] runtimeclass App : Microsoft.Toolkit.Win32.UI.XamlHost.XamlApplication
+    [default_interface] runtimeclass App : Windows.UI.Xaml.Application, Windows.Foundation.IClosable
     {
         App();
 
         SampleAppLogic Logic { get; };
+
+        Boolean IsDisposed { get; };
     }
 }

scratch/ScratchIslandApp/SampleApp/App.xaml

@@ -2,20 +2,19 @@
     Copyright (c) Microsoft Corporation. All rights reserved. Licensed under
     the MIT License. See LICENSE in the project root for license information.
 -->
-<Toolkit:XamlApplication x:Class="SampleApp.App"
-                         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
-                         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-                         xmlns:TA="using:SampleApp"
-                         xmlns:Toolkit="using:Microsoft.Toolkit.Win32.UI.XamlHost"
-                         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
-                         xmlns:local="using:SampleApp"
-                         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
-                         mc:Ignorable="d">
+<Application x:Class="SampleApp.App"
+             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:TA="using:SampleApp"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+             xmlns:local="using:SampleApp"
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             mc:Ignorable="d">
     <!--
         If you want to prove this works, then add `RequestedTheme="Light"` to
         the properties on the XamlApplication
     -->
-    <Toolkit:XamlApplication.Resources>
+    <Application.Resources>
 
         <ResourceDictionary>
             <ResourceDictionary.MergedDictionaries>
@@ -67,5 +66,5 @@
         </ResourceDictionary>
 
 
-    </Toolkit:XamlApplication.Resources>
-</Toolkit:XamlApplication>
+    </Application.Resources>
+</Application>

scratch/ScratchIslandApp/SampleApp/SampleAppLib.vcxproj

@@ -20,7 +20,6 @@
 
   <PropertyGroup Label="NuGet Dependencies">
     <TerminalCppWinrt>true</TerminalCppWinrt>
-    <TerminalXamlApplicationToolkit>true</TerminalXamlApplicationToolkit>
   </PropertyGroup>
   <Import Project="..\..\..\common.openconsole.props" Condition="'$(OpenConsoleDir)'==''" />
   <Import Project="$(OpenConsoleDir)src\common.nugetversions.props" />
@@ -128,6 +127,16 @@
       <Private>false</Private>
       <CopyLocalSatelliteAssemblies>false</CopyLocalSatelliteAssemblies>
     </Reference>
+
+    <Reference Include="$(WindowsSDK_MetadataPathVersioned)\Windows.UI.Xaml.Hosting.HostingContract\*\*.winmd">
+      <WinMDFile>true</WinMDFile>
+      <CopyLocal>false</CopyLocal>
+      <ReferenceGrouping>$(TargetPlatformMoniker)</ReferenceGrouping>
+      <ReferenceGroupingDisplayName>$(TargetPlatformDisplayName)</ReferenceGroupingDisplayName>
+      <ResolvedFrom>CppWinRTImplicitlyExpandTargetPlatform</ResolvedFrom>
+      <IsSystemReference>True</IsSystemReference>
+    </Reference>
+
   </ItemGroup>
   <!-- ====================== Compiler & Linker Flags ===================== -->
   <ItemDefinitionGroup>
@@ -147,12 +156,12 @@
   <!-- This -must- go after cppwinrt.build.post.props because that includes many VS-provided props including appcontainer.common.props, which stomps on what cppwinrt.targets did. -->
   <Import Project="$(OpenConsoleDir)src\common.nugetversions.targets" />
 
-  <Import Project="$(OpenConsoleDir)packages\Microsoft.UI.Xaml.2.7.3\build\native\Microsoft.UI.Xaml.targets" Condition="Exists('$(OpenConsoleDir)packages\Microsoft.UI.Xaml.2.7.3\build\native\Microsoft.UI.Xaml.targets')" />
+  <Import Project="$(OpenConsoleDir)packages\Microsoft.UI.Xaml.$(TerminalMUXVersion)\build\native\Microsoft.UI.Xaml.targets" Condition="Exists('$(OpenConsoleDir)packages\Microsoft.UI.Xaml.$(TerminalMUXVersion)\build\native\Microsoft.UI.Xaml.targets')" />
   <Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
     <PropertyGroup>
       <ErrorText>This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
     </PropertyGroup>
-    <Error Condition="!Exists('$(OpenConsoleDir)packages\Microsoft.UI.Xaml.2.7.3\build\native\Microsoft.UI.Xaml.targets')" Text="$([System.String]::Format('$(ErrorText)', '$(OpenConsoleDir)\packages\Microsoft.UI.Xaml.2.7.3\build\native\Microsoft.UI.Xaml.targets'))" />
+    <Error Condition="!Exists('$(OpenConsoleDir)packages\Microsoft.UI.Xaml.$(TerminalMUXVersion)\build\native\Microsoft.UI.Xaml.targets')" Text="$([System.String]::Format('$(ErrorText)', '$(OpenConsoleDir)\packages\Microsoft.UI.Xaml.$(TerminalMUXVersion)\build\native\Microsoft.UI.Xaml.targets'))" />
   </Target>
 
   <!--

scratch/ScratchIslandApp/SampleApp/dll/SampleApp.vcxproj

@@ -13,7 +13,6 @@
   </PropertyGroup>
   <PropertyGroup Label="NuGet Dependencies">
     <TerminalCppWinrt>true</TerminalCppWinrt>
-    <TerminalXamlApplicationToolkit>true</TerminalXamlApplicationToolkit>
   </PropertyGroup>
   <Import Project="..\..\..\..\common.openconsole.props" Condition="'$(OpenConsoleDir)'==''" />
   <Import Project="$(OpenConsoleDir)src\common.nugetversions.props" />
@@ -91,12 +90,12 @@
     </Link>
   </ItemDefinitionGroup>
 
-  <Import Project="$(OpenConsoleDir)packages\Microsoft.UI.Xaml.2.7.3\build\native\Microsoft.UI.Xaml.targets" Condition="Exists('$(OpenConsoleDir)packages\Microsoft.UI.Xaml.2.7.3\build\native\Microsoft.UI.Xaml.targets')" />
+  <Import Project="$(OpenConsoleDir)packages\Microsoft.UI.Xaml.$(TerminalMUXVersion)\build\native\Microsoft.UI.Xaml.targets" Condition="Exists('$(OpenConsoleDir)packages\Microsoft.UI.Xaml.$(TerminalMUXVersion)\build\native\Microsoft.UI.Xaml.targets')" />
   <Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
     <PropertyGroup>
       <ErrorText>This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
     </PropertyGroup>
-    <Error Condition="!Exists('$(OpenConsoleDir)\packages\Microsoft.UI.Xaml.2.7.3\build\native\Microsoft.UI.Xaml.targets')" Text="$([System.String]::Format('$(ErrorText)', '$(OpenConsoleDir)\packages\Microsoft.UI.Xaml.2.7.3\build\native\Microsoft.UI.Xaml.targets'))" />
+    <Error Condition="!Exists('$(OpenConsoleDir)\packages\Microsoft.UI.Xaml.$(TerminalMUXVersion)\build\native\Microsoft.UI.Xaml.targets')" Text="$([System.String]::Format('$(ErrorText)', '$(OpenConsoleDir)\packages\Microsoft.UI.Xaml.$(TerminalMUXVersion)\build\native\Microsoft.UI.Xaml.targets'))" />
   </Target>
 
   <ItemDefinitionGroup>

scratch/ScratchIslandApp/WindowExe/SampleAppHost.cpp

@@ -16,13 +16,10 @@ using namespace winrt::Windows::Foundation::Numerics;
 using namespace ::Microsoft::Console;
 using namespace ::Microsoft::Console::Types;
 
-SampleAppHost::SampleAppHost() noexcept :
-    _app{},
-    _logic{ nullptr }, // don't make one, we're going to take a ref on app's
+SampleAppHost::SampleAppHost(winrt::SampleApp::SampleAppLogic l) noexcept :
+    _logic{ l }, 
     _window{ nullptr }
 {
-    _logic = _app.Logic(); // get a ref to app's logic
-
     _window = std::make_unique<SampleIslandWindow>();
     _window->MakeWindow();
 }
@@ -31,8 +28,8 @@ SampleAppHost::~SampleAppHost()
 {
     // destruction order is important for proper teardown here
     _window = nullptr;
-    _app.Close();
-    _app = nullptr;
+    // _app.Close();
+    // _app = nullptr;
 }
 // Method Description:
 // - Initializes the XAML island, creates the terminal app, and sets the
@@ -48,7 +45,7 @@ SampleAppHost::~SampleAppHost()
 void SampleAppHost::Initialize()
 {
     _window->Initialize();
-
+    _logic = winrt::SampleApp::SampleAppLogic();
     _logic.Create();
 
     _window->UpdateTitle(_logic.Title());
@@ -59,20 +56,4 @@ void SampleAppHost::Initialize()
 
     _window->OnAppInitialized();
 
-    // THIS IS A HACK
-    //
-    // We've got a weird crash that happens terribly inconsistently, only in
-    // Debug mode. Apparently, there's some weird ref-counting magic that goes
-    // on during teardown, and our Application doesn't get closed quite right,
-    // which can cause us to crash into the debugger. This of course, only
-    // happens on exit, and happens somewhere in the XamlHost.dll code.
-    //
-    // Crazily, if we _manually leak the Application_ here, then the crash
-    // doesn't happen. This doesn't matter, because we really want the
-    // Application to live for _the entire lifetime of the process_, so the only
-    // time when this object would actually need to get cleaned up is _during
-    // exit_. So we can safely leak this Application object, and have it just
-    // get cleaned up normally when our process exits.
-    ::winrt::SampleApp::App a{ _app };
-    ::winrt::detach_abi(a);
 }

scratch/ScratchIslandApp/WindowExe/SampleAppHost.h

@@ -8,13 +8,13 @@
 class SampleAppHost
 {
 public:
-    SampleAppHost() noexcept;
+    SampleAppHost(winrt::SampleApp::SampleAppLogic l) noexcept;
     virtual ~SampleAppHost();
 
     void Initialize();
 
+    winrt::SampleApp::SampleAppLogic _logic{ nullptr };
+
 private:
     std::unique_ptr<SampleIslandWindow> _window;
-    winrt::SampleApp::App _app;
-    winrt::SampleApp::SampleAppLogic _logic;
 };

scratch/ScratchIslandApp/WindowExe/SampleMain.cpp

@@ -74,6 +74,9 @@ static bool _messageIsAltKeyup(const MSG& message)
     return (message.message == WM_KEYUP || message.message == WM_SYSKEYUP) && message.wParam == VK_MENU;
 }
 
+int foo();
+winrt::SampleApp::App g_app{ nullptr };
+
 int __stdcall wWinMain(HINSTANCE, HINSTANCE, LPWSTR, int)
 {
     // If Terminal is spawned by a shortcut that requests that it run in a new process group
@@ -91,6 +94,24 @@ int __stdcall wWinMain(HINSTANCE, HINSTANCE, LPWSTR, int)
     // Make sure to call this so we get WM_POINTER messages.
     EnableMouseInPointer(true);
 
+    winrt::init_apartment(winrt::apartment_type::single_threaded);
+
+    // Create the App first, on the main thread
+    g_app = winrt::SampleApp::App();
+
+    std::thread one(foo);
+
+    Sleep(2000);
+    std::thread two(foo);
+
+    one.join();
+    // two.join();
+
+    return 0;
+}
+
+int foo(){
+
     // !!! LOAD BEARING !!!
     // We must initialize the main thread as a single-threaded apartment before
     // constructing any Xaml objects. Failing to do so will cause some issues
@@ -105,7 +126,9 @@ int __stdcall wWinMain(HINSTANCE, HINSTANCE, LPWSTR, int)
     // Create the SampleAppHost object, which will create both the window and the
     // Terminal App. This MUST BE constructed before the Xaml manager as TermApp
     // provides an implementation of Windows.UI.Xaml.Application.
-    SampleAppHost host;
+    SampleAppHost host{ nullptr };
+
+    // host._logic = winrt::SampleApp::SampleAppLogic(); // This calls to winrt::make_self<MyPage>();
 
     // Initialize the xaml content. This must be called AFTER the
     // WindowsXamlManager is initialized.

scratch/ScratchIslandApp/WindowExe/WindowExe.vcxproj

@@ -144,12 +144,12 @@
 
   <Import Project="$(OpenConsoleDir)src\cppwinrt.build.post.props" />
 
-  <Import Project="..\..\..\packages\Microsoft.UI.Xaml.2.7.3\build\native\Microsoft.UI.Xaml.targets" Condition="Exists('..\..\..\packages\Microsoft.UI.Xaml.2.7.3\build\native\Microsoft.UI.Xaml.targets')" />
+  <Import Project="..\..\..\packages\Microsoft.UI.Xaml.$(TerminalMUXVersion)\build\native\Microsoft.UI.Xaml.targets" Condition="Exists('..\..\..\packages\Microsoft.UI.Xaml.$(TerminalMUXVersion)\build\native\Microsoft.UI.Xaml.targets')" />
   <Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
     <PropertyGroup>
       <ErrorText>This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
     </PropertyGroup>
-    <Error Condition="!Exists('..\..\..\packages\Microsoft.UI.Xaml.2.7.3\build\native\Microsoft.UI.Xaml.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\..\..\packages\Microsoft.UI.Xaml.2.7.3\build\native\Microsoft.UI.Xaml.targets'))" />
+    <Error Condition="!Exists('..\..\..\packages\Microsoft.UI.Xaml.$(TerminalMUXVersion)\build\native\Microsoft.UI.Xaml.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\..\..\packages\Microsoft.UI.Xaml.$(TerminalMUXVersion)\build\native\Microsoft.UI.Xaml.targets'))" />
   </Target>
 
   <!-- Override GetPackagingOutputs to roll up all our dependencies.

src/cascadia/LocalTests_TerminalApp/TerminalApp.LocalTests.vcxproj

@@ -23,7 +23,6 @@
 
   <PropertyGroup Label="NuGet Dependencies">
     <!-- TerminalCppWinrt is intentionally not set -->
-    <TerminalXamlApplicationToolkit>true</TerminalXamlApplicationToolkit>
   </PropertyGroup>
 
   <Import Project="$(SolutionDir)\common.openconsole.props" Condition="'$(OpenConsoleDir)'==''" />

src/cascadia/TerminalApp/App.cpp

@@ -12,19 +12,12 @@ using namespace winrt::Windows::UI::Xaml;
 using namespace winrt::Windows::UI::Xaml::Controls;
 using namespace winrt::Windows::UI::Xaml::Navigation;
 
+namespace xaml = ::winrt::Windows::UI::Xaml;
+
 namespace winrt::TerminalApp::implementation
 {
     App::App()
     {
-        // This is the same trick that Initialize() is about to use to figure out whether we're coming
-        // from a UWP context or from a Win32 context
-        // See https://github.com/windows-toolkit/Microsoft.Toolkit.Win32/blob/52611c57d89554f357f281d0c79036426a7d9257/Microsoft.Toolkit.Win32.UI.XamlApplication/XamlApplication.cpp#L42
-        const auto dispatcherQueue = ::winrt::Windows::System::DispatcherQueue::GetForCurrentThread();
-        if (dispatcherQueue)
-        {
-            _isUwp = true;
-        }
-
         Initialize();
 
         // Disable XAML's automatic backplating of text when in High Contrast
@@ -33,12 +26,50 @@ namespace winrt::TerminalApp::implementation
         HighContrastAdjustment(::winrt::Windows::UI::Xaml::ApplicationHighContrastAdjustment::None);
     }
 
+    void App::Initialize()
+    {
+        const auto dispatcherQueue = winrt::Windows::System::DispatcherQueue::GetForCurrentThread();
+        if (!dispatcherQueue)
+        {
+            _windowsXamlManager = xaml::Hosting::WindowsXamlManager::InitializeForCurrentThread();
+        }
+        else
+        {
+            _isUwp = true;
+        }
+    }
+
     AppLogic App::Logic()
     {
         static AppLogic logic;
         return logic;
     }
 
+    void App::Close()
+    {
+        if (_bIsClosed)
+        {
+            return;
+        }
+
+        _bIsClosed = true;
+
+        if (_windowsXamlManager)
+        {
+            _windowsXamlManager.Close();
+        }
+        _windowsXamlManager = nullptr;
+
+        Exit();
+        {
+            MSG msg = {};
+            while (PeekMessageW(&msg, nullptr, 0, 0, PM_REMOVE))
+            {
+                ::DispatchMessageW(&msg);
+            }
+        }
+    }
+
     /// <summary>
     /// Invoked when the application is launched normally by the end user.  Other entry points
     /// will be used such as when the application is launched to open a specific file.

src/cascadia/TerminalApp/App.h

@@ -5,6 +5,7 @@
 
 #include "App.g.h"
 #include "App.base.h"
+#include <winrt/Windows.UI.Xaml.Hosting.h>
 
 namespace winrt::TerminalApp::implementation
 {
@@ -13,11 +14,22 @@ namespace winrt::TerminalApp::implementation
     public:
         App();
         void OnLaunched(const Windows::ApplicationModel::Activation::LaunchActivatedEventArgs&);
+        void Initialize();
 
         TerminalApp::AppLogic Logic();
 
+        void Close();
+
+        bool IsDisposed() const
+        {
+            return _bIsClosed;
+        }
+
     private:
         bool _isUwp = false;
+        winrt::Windows::UI::Xaml::Hosting::WindowsXamlManager _windowsXamlManager = nullptr;
+        winrt::Windows::Foundation::Collections::IVector<winrt::Windows::UI::Xaml::Markup::IXamlMetadataProvider> _providers = winrt::single_threaded_vector<Windows::UI::Xaml::Markup::IXamlMetadataProvider>();
+        bool _bIsClosed = false;
     };
 }
 

src/cascadia/TerminalApp/App.idl

@@ -7,10 +7,12 @@ namespace TerminalApp
 {
     // ADD ARBITRARY APP LOGIC TO AppLogic.idl, NOT HERE.
     // This is for XAML platform setup only.
-    [default_interface] runtimeclass App : Microsoft.Toolkit.Win32.UI.XamlHost.XamlApplication
+    [default_interface] runtimeclass App : Windows.UI.Xaml.Application, Windows.Foundation.IClosable
     {
         App();
 
         AppLogic Logic { get; };
+
+        Boolean IsDisposed { get; };
     }
 }

src/cascadia/TerminalApp/App.xaml

@@ -2,11 +2,10 @@
     Copyright (c) Microsoft Corporation. All rights reserved. Licensed under
     the MIT License. See LICENSE in the project root for license information.
 -->
-<Toolkit:XamlApplication x:Class="TerminalApp.App"
+<Application x:Class="TerminalApp.App"
                          xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                          xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                          xmlns:TA="using:TerminalApp"
-                         xmlns:Toolkit="using:Microsoft.Toolkit.Win32.UI.XamlHost"
                          xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
                          xmlns:local="using:TerminalApp"
                          xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
@@ -15,7 +14,7 @@
         If you want to prove this works, then add `RequestedTheme="Light"` to
         the properties on the XamlApplication
     -->
-    <Toolkit:XamlApplication.Resources>
+    <Application.Resources>
 
         <ResourceDictionary>
             <ResourceDictionary.MergedDictionaries>
@@ -202,5 +201,5 @@
         </ResourceDictionary>
 
 
-    </Toolkit:XamlApplication.Resources>
-</Toolkit:XamlApplication>
+    </Application.Resources>
+</Application>

src/cascadia/TerminalApp/TerminalAppLib.vcxproj

@@ -19,7 +19,6 @@
   </PropertyGroup>
   <PropertyGroup Label="NuGet Dependencies">
     <TerminalCppWinrt>true</TerminalCppWinrt>
-    <TerminalXamlApplicationToolkit>true</TerminalXamlApplicationToolkit>
     <TerminalMUX>true</TerminalMUX>
   </PropertyGroup>
   <Import Project="..\..\..\common.openconsole.props" Condition="'$(OpenConsoleDir)'==''" />
@@ -382,6 +381,14 @@
       <Private>false</Private>
       <CopyLocalSatelliteAssemblies>false</CopyLocalSatelliteAssemblies>
     </Reference>
+    <Reference Include="$(WindowsSDK_MetadataPathVersioned)\Windows.UI.Xaml.Hosting.HostingContract\*\*.winmd">
+      <WinMDFile>true</WinMDFile>
+      <CopyLocal>false</CopyLocal>
+      <ReferenceGrouping>$(TargetPlatformMoniker)</ReferenceGrouping>
+      <ReferenceGroupingDisplayName>$(TargetPlatformDisplayName)</ReferenceGroupingDisplayName>
+      <ResolvedFrom>CppWinRTImplicitlyExpandTargetPlatform</ResolvedFrom>
+      <IsSystemReference>True</IsSystemReference>
+    </Reference>
   </ItemGroup>
   <!-- ====================== Compiler & Linker Flags ===================== -->
   <ItemDefinitionGroup>

src/cascadia/TerminalApp/dll/TerminalApp.vcxproj

@@ -14,7 +14,6 @@
   </PropertyGroup>
   <PropertyGroup Label="NuGet Dependencies">
     <TerminalCppWinrt>true</TerminalCppWinrt>
-    <TerminalXamlApplicationToolkit>true</TerminalXamlApplicationToolkit>
     <TerminalMUX>true</TerminalMUX>
   </PropertyGroup>
   <Import Project="..\..\..\..\common.openconsole.props" Condition="'$(OpenConsoleDir)'==''" />

src/cascadia/WindowsTerminal/WindowsTerminal.vcxproj

@@ -18,7 +18,6 @@
 
   <PropertyGroup Label="NuGet Dependencies">
     <TerminalCppWinrt>true</TerminalCppWinrt>
-    <TerminalXamlApplicationToolkit>true</TerminalXamlApplicationToolkit>
     <TerminalVCRTForwarders>true</TerminalVCRTForwarders>
     <TerminalThemeHelpers>true</TerminalThemeHelpers>
     <TerminalMUX>true</TerminalMUX>

src/common.nugetversions.props

@@ -6,9 +6,6 @@
   <!-- CppWinrt -->
   <Import Project="$(MSBuildThisFileDirectory)..\packages\Microsoft.Windows.CppWinRT.2.0.210825.3\build\native\Microsoft.Windows.CppWinRT.props" Condition="'$(TerminalCppWinrt)' == 'true' and Exists('$(MSBuildThisFileDirectory)..\packages\Microsoft.Windows.CppWinRT.2.0.210825.3\build\native\Microsoft.Windows.CppWinRT.props')" />
 
-  <!-- XamlApplicationToolkit -->
-  <Import Project="$(MSBuildThisFileDirectory)..\packages\Microsoft.Toolkit.Win32.UI.XamlApplication.6.1.3\build\native\Microsoft.Toolkit.Win32.UI.XamlApplication.props" Condition="'$(TerminalXamlApplicationToolkit)'  == 'true' and Exists('$(MSBuildThisFileDirectory)..\packages\Microsoft.Toolkit.Win32.UI.XamlApplication.6.1.3\build\native\Microsoft.Toolkit.Win32.UI.XamlApplication.props')" />
-
   <!-- TAEF -->
   <PropertyGroup>
     <TAEFPackagePathRoot>$(MSBuildThisFileDirectory)..\packages\Microsoft.Taef.10.60.210621002</TAEFPackagePathRoot>

src/common.nugetversions.targets

@@ -40,9 +40,6 @@
     <!-- CppWinrt -->
     <Import Project="$(MSBuildThisFileDirectory)..\packages\Microsoft.Windows.CppWinRT.2.0.210825.3\build\native\Microsoft.Windows.CppWinRT.targets" Condition="'$(TerminalCppWinrt)' == 'true' and Exists('$(MSBuildThisFileDirectory)..\packages\Microsoft.Windows.CppWinRT.2.0.210825.3\build\native\Microsoft.Windows.CppWinRT.targets')" />
 
-    <!-- XamlApplicationToolkit -->
-    <Import Project="$(MSBuildThisFileDirectory)..\packages\Microsoft.Toolkit.Win32.UI.XamlApplication.6.1.3\build\native\Microsoft.Toolkit.Win32.UI.XamlApplication.targets" Condition="'$(TerminalXamlApplicationToolkit)' == 'true' and Exists('$(MSBuildThisFileDirectory)..\packages\Microsoft.Toolkit.Win32.UI.XamlApplication.6.1.3\build\native\Microsoft.Toolkit.Win32.UI.XamlApplication.targets')" />
-
     <!-- TAEF -->
     <Import Project="$(MSBuildThisFileDirectory)..\packages\Microsoft.Taef.10.60.210621002\build\Microsoft.Taef.targets" Condition="'$(TerminalTAEF)' == 'true' and Exists('$(MSBuildThisFileDirectory)..\packages\Microsoft.Taef.10.60.210621002\build\Microsoft.Taef.targets')" />
     
@@ -79,10 +76,6 @@
     <Error Condition="'$(TerminalCppWinrt)' == 'true' AND !Exists('$(MSBuildThisFileDirectory)..\packages\Microsoft.Windows.CppWinRT.2.0.210825.3\build\native\Microsoft.Windows.CppWinRT.props')" Text="$([System.String]::Format('$(ErrorText)', '$(MSBuildThisFileDirectory)..\packages\Microsoft.Windows.CppWinRT.2.0.210825.3\build\native\Microsoft.Windows.CppWinRT.props'))" />
     <Error Condition="'$(TerminalCppWinrt)' == 'true' AND !Exists('$(MSBuildThisFileDirectory)..\packages\Microsoft.Windows.CppWinRT.2.0.210825.3\build\native\Microsoft.Windows.CppWinRT.targets')" Text="$([System.String]::Format('$(ErrorText)', '$(MSBuildThisFileDirectory)..\packages\Microsoft.Windows.CppWinRT.2.0.210825.3\build\native\Microsoft.Windows.CppWinRT.targets'))" />
 
-    <!-- XamlApplicationToolkit -->
-    <Error Condition="'$(TerminalXamlApplicationToolkit)' == 'true' AND !Exists('$(MSBuildThisFileDirectory)..\packages\Microsoft.Toolkit.Win32.UI.XamlApplication.6.1.3\build\native\Microsoft.Toolkit.Win32.UI.XamlApplication.props')" Text="$([System.String]::Format('$(ErrorText)', '$(MSBuildThisFileDirectory)..\packages\Microsoft.Toolkit.Win32.UI.XamlApplication.6.1.3\build\native\Microsoft.Toolkit.Win32.UI.XamlApplication.props'))" />
-    <Error Condition="'$(TerminalXamlApplicationToolkit)' == 'true' AND !Exists('$(MSBuildThisFileDirectory)..\packages\Microsoft.Toolkit.Win32.UI.XamlApplication.6.1.3\build\native\Microsoft.Toolkit.Win32.UI.XamlApplication.targets')" Text="$([System.String]::Format('$(ErrorText)', '$(MSBuildThisFileDirectory)..\packages\Microsoft.Toolkit.Win32.UI.XamlApplication.6.1.3\build\native\Microsoft.Toolkit.Win32.UI.XamlApplication.targets'))" />
-
     <!-- TAEF -->
     <Error Condition="'$(TerminalTAEF)' == 'true' AND !Exists('$(MSBuildThisFileDirectory)..\packages\Microsoft.Taef.10.60.210621002\build\Microsoft.Taef.targets')" Text="$([System.String]::Format('$(ErrorText)', '$(MSBuildThisFileDirectory)..\packages\Microsoft.Taef.10.60.210621002\build\Microsoft.Taef.targets'))" />