Migrate ApplicationViewModel to C# (#2353)

* migrate ApplicationViewModel to C# * fix aot mode * save ctor
2025-08-21 05:43:10 -07:00 · 2025-07-09 16:39:03 +08:00 · 2025-07-09 16:39:03 +08:00 · 5b21e4c58b
commit 5b21e4c58b
parent 4f16eca81d
21 changed files with 691 additions and 482 deletions
--- a/src/CalcViewModel/ApplicationViewModel.cpp
+++ b/src/CalcViewModel/ApplicationViewModel.cpp
@ -1,293 +0,0 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
-// Licensed under the MIT License.
-
-#include "pch.h"
-#include "ApplicationViewModel.h"
-#include "Common/TraceLogger.h"
-#include "Common/AppResourceProvider.h"
-#include "StandardCalculatorViewModel.h"
-#include "DateCalculatorViewModel.h"
-#include "DataLoaders/CurrencyHttpClient.h"
-#include "DataLoaders/CurrencyDataLoader.h"
-#include "DataLoaders/UnitConverterDataLoader.h"
-
-using namespace CalculatorApp;
-using namespace CalculatorApp::ViewModel::Common;
-using namespace CalculatorApp::ViewModel::DataLoaders;
-using namespace CalculatorApp::ViewModel;
-using namespace CalculationManager;
-using namespace Platform;
-using namespace Platform::Collections;
-using namespace Windows::System;
-using namespace Windows::Storage;
-using namespace Utils;
-using namespace Windows::Foundation::Collections;
-using namespace Windows::Globalization;
-using namespace Windows::UI::ViewManagement;
-using namespace Windows::UI::Core;
-using namespace Windows::UI::Xaml::Automation;
-using namespace Windows::UI::Xaml::Controls;
-using namespace Windows::UI::Xaml::Data;
-using namespace Windows::UI::Xaml::Input;
-using namespace Windows::UI::Xaml::Media;
-using namespace Windows::Foundation;
-using namespace Concurrency;
-
-namespace
-{
-    StringReference CategoriesPropertyName(L"Categories");
-    StringReference ClearMemoryVisibilityPropertyName(L"ClearMemoryVisibility");
-}
-
-ApplicationViewModel::ApplicationViewModel()
-    : m_CalculatorViewModel(nullptr)
-    , m_DateCalcViewModel(nullptr)
-    , m_GraphingCalcViewModel(nullptr)
-    , m_ConverterViewModel(nullptr)
-    , m_PreviousMode(ViewMode::None)
-    , m_mode(ViewMode::None)
-    , m_categories(nullptr)
-{
-    SetMenuCategories();
-}
-
-void ApplicationViewModel::Mode::set(ViewMode value)
-{
-    if (m_mode != value)
-    {
-        PreviousMode = m_mode;
-        m_mode = value;
-        SetDisplayNormalAlwaysOnTopOption();
-        OnModeChanged();
-        RaisePropertyChanged(ModePropertyName);
-    }
-}
-
-void ApplicationViewModel::Categories::set(IObservableVector<NavCategoryGroup ^> ^ value)
-{
-    if (m_categories != value)
-    {
-        m_categories = value;
-        RaisePropertyChanged(CategoriesPropertyName);
-    }
-}
-
-CalculatorApp::ViewModel::Snapshot::ApplicationSnapshot ^ ApplicationViewModel::Snapshot::get()
-{
-    auto snapshot = ref new CalculatorApp::ViewModel::Snapshot::ApplicationSnapshot();
-    snapshot->Mode = static_cast<int>(Mode);
-    if (m_CalculatorViewModel != nullptr && m_mode == ViewMode::Standard)
-    {
-        snapshot->StandardCalculator = m_CalculatorViewModel->Snapshot;
-    }
-    return snapshot;
-}
-
-void ApplicationViewModel::Initialize(ViewMode mode)
-{
-    if (!NavCategoryStates::IsValidViewMode(mode) || !NavCategoryStates::IsViewModeEnabled(mode))
-    {
-        mode = ViewMode::Standard;
-    }
-
-    try
-    {
-        Mode = mode;
-    }
-    catch (const std::exception& e)
-    {
-        TraceLogger::GetInstance()->LogStandardException(mode, __FUNCTIONW__, e);
-        if (!TryRecoverFromNavigationModeFailure())
-        {
-            // Could not navigate to standard mode either.
-            // Throw the original exception so we have a good stack to debug.
-            throw;
-        }
-    }
-    catch (Exception ^ e)
-    {
-        TraceLogger::GetInstance()->LogPlatformException(mode, __FUNCTIONW__, e);
-        if (!TryRecoverFromNavigationModeFailure())
-        {
-            // Could not navigate to standard mode either.
-            // Throw the original exception so we have a good stack to debug.
-            throw;
-        }
-    }
-}
-
-void ApplicationViewModel::RestoreFromSnapshot(CalculatorApp::ViewModel::Snapshot::ApplicationSnapshot ^ snapshot)
-{
-    Mode = static_cast<ViewMode>(snapshot->Mode);
-    if (snapshot->StandardCalculator != nullptr)
-    {
-        m_CalculatorViewModel->Snapshot = snapshot->StandardCalculator;
-    }
-}
-
-bool ApplicationViewModel::TryRecoverFromNavigationModeFailure()
-{
-    // Here we are simply trying to recover from being unable to navigate to a mode.
-    // Try falling back to standard mode and if there are *any* exceptions, we should
-    // fail because something is seriously wrong.
-    try
-    {
-        Mode = ViewMode::Standard;
-        return true;
-    }
-    catch (...)
-    {
-        return false;
-    }
-}
-
-void ApplicationViewModel::OnModeChanged()
-{
-    assert(NavCategoryStates::IsValidViewMode(m_mode));
-    if (NavCategory::IsCalculatorViewMode(m_mode))
-    {
-        if (!m_CalculatorViewModel)
-        {
-            m_CalculatorViewModel = ref new StandardCalculatorViewModel();
-        }
-        m_CalculatorViewModel->SetCalculatorType(m_mode);
-    }
-    else if (NavCategory::IsGraphingCalculatorViewMode(m_mode))
-    {
-        if (!m_GraphingCalcViewModel)
-        {
-            m_GraphingCalcViewModel = ref new GraphingCalculatorViewModel();
-        }
-    }
-    else if (NavCategory::IsDateCalculatorViewMode(m_mode))
-    {
-        if (!m_DateCalcViewModel)
-        {
-            m_DateCalcViewModel = ref new DateCalculatorViewModel();
-        }
-    }
-    else if (NavCategory::IsConverterViewMode(m_mode))
-    {
-        if (!m_ConverterViewModel)
-        {
-            auto dataLoader = std::make_shared<UnitConverterDataLoader>(ref new GeographicRegion());
-            m_ConverterViewModel =
-                ref new UnitConverterViewModel(std::make_shared<UnitConversionManager::UnitConverter>(dataLoader, std::make_shared<CurrencyDataLoader>()));
-        }
-
-        m_ConverterViewModel->Mode = m_mode;
-    }
-
-    auto resProvider = AppResourceProvider::GetInstance();
-    CategoryName = resProvider->GetResourceString(NavCategoryStates::GetNameResourceKey(m_mode));
-
-    // Cast mode to an int in order to save it to app data.
-    // Save the changed mode, so that the new window launches in this mode.
-    // Don't save until after we have adjusted to the new mode, so we don't save a mode that fails to load.
-    ApplicationData::Current->LocalSettings->Values->Insert(ModePropertyName, NavCategoryStates::Serialize(m_mode));
-
-    // Log ModeChange event when not first launch, log WindowCreated on first launch
-    if (NavCategoryStates::IsValidViewMode(m_PreviousMode))
-    {
-        TraceLogger::GetInstance()->LogModeChange(m_mode);
-    }
-    else
-    {
-        TraceLogger::GetInstance()->LogWindowCreated(m_mode, ApplicationView::GetApplicationViewIdForWindow(CoreWindow::GetForCurrentThread()));
-    }
-
-    RaisePropertyChanged(ClearMemoryVisibilityPropertyName);
-}
-
-void ApplicationViewModel::OnCopyCommand(Object ^ parameter)
-{
-    if (NavCategory::IsConverterViewMode(m_mode))
-    {
-        ConverterViewModel->OnCopyCommand(parameter);
-    }
-    else if (NavCategory::IsDateCalculatorViewMode(m_mode))
-    {
-        DateCalcViewModel->OnCopyCommand(parameter);
-    }
-    else if (NavCategory::IsCalculatorViewMode(m_mode))
-    {
-        CalculatorViewModel->OnCopyCommand(parameter);
-    }
-}
-
-void ApplicationViewModel::OnPasteCommand(Object ^ parameter)
-{
-    if (NavCategory::IsConverterViewMode(m_mode))
-    {
-        ConverterViewModel->OnPasteCommand(parameter);
-    }
-    else if (NavCategory::IsCalculatorViewMode(m_mode))
-    {
-        CalculatorViewModel->OnPasteCommand(parameter);
-    }
-}
-
-void ApplicationViewModel::SetMenuCategories()
-{
-    // Use the Categories property instead of the backing variable
-    // because we want to take advantage of binding updates and
-    // property setter logic.
-    Categories = NavCategoryStates::CreateMenuOptions();
-}
-
-void ApplicationViewModel::ToggleAlwaysOnTop(float width, float height)
-{
-    HandleToggleAlwaysOnTop(width, height);
-}
-
-#pragma optimize("", off)
-task<void> ApplicationViewModel::HandleToggleAlwaysOnTop(float width, float height)
-{
-    if (ApplicationView::GetForCurrentView()->ViewMode == ApplicationViewMode::CompactOverlay)
-    {
-        ApplicationDataContainer ^ localSettings = ApplicationData::Current->LocalSettings;
-        localSettings->Values->Insert(WidthLocalSettings, width);
-        localSettings->Values->Insert(HeightLocalSettings, height);
-
-        bool success = co_await ApplicationView::GetForCurrentView()->TryEnterViewModeAsync(ApplicationViewMode::Default);
-        CalculatorViewModel->HistoryVM->AreHistoryShortcutsEnabled = success;
-        CalculatorViewModel->IsAlwaysOnTop = !success;
-        IsAlwaysOnTop = !success;
-    }
-    else
-    {
-        ApplicationDataContainer ^ localSettings = ApplicationData::Current->LocalSettings;
-        ViewModePreferences ^ compactOptions = ViewModePreferences::CreateDefault(ApplicationViewMode::CompactOverlay);
-        if (!localSettings->Values->GetView()->HasKey(LaunchedLocalSettings))
-        {
-            compactOptions->CustomSize = Size(320, 394);
-            localSettings->Values->Insert(LaunchedLocalSettings, true);
-        }
-        else
-        {
-            if (localSettings->Values->GetView()->HasKey(WidthLocalSettings) && localSettings->Values->GetView()->HasKey(HeightLocalSettings))
-            {
-                float oldWidth = safe_cast<IPropertyValue ^>(localSettings->Values->GetView()->Lookup(WidthLocalSettings))->GetSingle();
-                float oldHeight = safe_cast<IPropertyValue ^>(localSettings->Values->GetView()->Lookup(HeightLocalSettings))->GetSingle();
-                compactOptions->CustomSize = Size(oldWidth, oldHeight);
-            }
-            else
-            {
-                compactOptions->CustomSize = Size(320, 394);
-            }
-        }
-
-        bool success = co_await ApplicationView::GetForCurrentView()->TryEnterViewModeAsync(ApplicationViewMode::CompactOverlay, compactOptions);
-        CalculatorViewModel->HistoryVM->AreHistoryShortcutsEnabled = !success;
-        CalculatorViewModel->IsAlwaysOnTop = success;
-        IsAlwaysOnTop = success;
-    }
-    SetDisplayNormalAlwaysOnTopOption();
-};
-#pragma optimize("", on)
-
-void ApplicationViewModel::SetDisplayNormalAlwaysOnTopOption()
-{
-    DisplayNormalAlwaysOnTopOption =
-        m_mode == ViewMode::Standard && ApplicationView::GetForCurrentView()->IsViewModeSupported(ApplicationViewMode::CompactOverlay) && !IsAlwaysOnTop;
-}
--- a/src/CalcViewModel/ApplicationViewModel.h
+++ b/src/CalcViewModel/ApplicationViewModel.h
@ -1,122 +0,0 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
-// Licensed under the MIT License.
-
-#pragma once
-
-#include "Snapshots.h"
-#include "StandardCalculatorViewModel.h"
-#include "DateCalculatorViewModel.h"
-#include "GraphingCalculator/GraphingCalculatorViewModel.h"
-#include "UnitConverterViewModel.h"
-
-namespace CalculatorApp
-{
-    namespace ViewModel
-    {
-        [Windows::UI::Xaml::Data::Bindable] public ref class ApplicationViewModel sealed : public Windows::UI::Xaml::Data::INotifyPropertyChanged
-        {
-        public:
-            ApplicationViewModel();
-
-            void Initialize(CalculatorApp::ViewModel::Common::ViewMode mode); // Use for first init, use deserialize for rehydration
-            void RestoreFromSnapshot(CalculatorApp::ViewModel::Snapshot::ApplicationSnapshot^ snapshot);
-
-            OBSERVABLE_OBJECT();
-            OBSERVABLE_PROPERTY_RW(StandardCalculatorViewModel ^, CalculatorViewModel);
-            OBSERVABLE_PROPERTY_RW(DateCalculatorViewModel ^, DateCalcViewModel);
-            OBSERVABLE_PROPERTY_RW(GraphingCalculatorViewModel ^, GraphingCalcViewModel);
-            OBSERVABLE_PROPERTY_RW(UnitConverterViewModel ^, ConverterViewModel);
-            OBSERVABLE_PROPERTY_RW(CalculatorApp::ViewModel::Common::ViewMode, PreviousMode);
-            OBSERVABLE_PROPERTY_R(bool, IsAlwaysOnTop);
-            OBSERVABLE_NAMED_PROPERTY_RW(Platform::String ^, CategoryName);
-
-            // Indicates whether calculator is currently in standard mode _and_ supports CompactOverlay _and_ is not in Always-on-Top mode
-            OBSERVABLE_PROPERTY_R(bool, DisplayNormalAlwaysOnTopOption);
-
-            COMMAND_FOR_METHOD(CopyCommand, ApplicationViewModel::OnCopyCommand);
-            COMMAND_FOR_METHOD(PasteCommand, ApplicationViewModel::OnPasteCommand);
-
-            property CalculatorApp::ViewModel::Common::ViewMode Mode
-            {
-                CalculatorApp::ViewModel::Common::ViewMode get()
-                {
-                    return m_mode;
-                }
-
-                void set(CalculatorApp::ViewModel::Common::ViewMode value);
-            }
-            static property Platform::String^ ModePropertyName
-            {
-                Platform::String^ get()
-                {
-                    return Platform::StringReference(L"Mode");
-                }
-            }
-
-            property Windows::Foundation::Collections::IObservableVector<CalculatorApp::ViewModel::Common::NavCategoryGroup^>^ Categories
-            {
-                Windows::Foundation::Collections::IObservableVector<CalculatorApp::ViewModel::Common::NavCategoryGroup^>^ get()
-                {
-                    return m_categories;
-                }
-
-                void set(Windows::Foundation::Collections::IObservableVector<CalculatorApp::ViewModel::Common::NavCategoryGroup^>^ value);
-            }
-
-            property Windows::UI::Xaml::Visibility ClearMemoryVisibility
-            {
-                Windows::UI::Xaml::Visibility get()
-                {
-                    return CalculatorApp::ViewModel::Common::NavCategory::IsCalculatorViewMode(Mode) ? Windows::UI::Xaml::Visibility::Visible
-                                                                                          : Windows::UI::Xaml::Visibility::Collapsed;
-                }
-            }
-
-            property CalculatorApp::ViewModel::Snapshot::ApplicationSnapshot  ^ Snapshot
-            {
-                CalculatorApp::ViewModel::Snapshot::ApplicationSnapshot ^ get();
-            }
-
-            static property Platform::String ^ LaunchedLocalSettings
-            {
-                Platform::String ^ get()
-                {
-                    return Platform::StringReference(L"calculatorAlwaysOnTopLaunched");
-                }
-            }
-
-            static property Platform::String ^ WidthLocalSettings
-            {
-                Platform::String ^ get()
-                {
-                    return Platform::StringReference(L"calculatorAlwaysOnTopLastWidth");
-                }
-            }
-
-            static property Platform::String ^ HeightLocalSettings
-            {
-                Platform::String ^ get()
-                {
-                    return Platform::StringReference(L"calculatorAlwaysOnTopLastHeight");
-                }
-            }
-
-            void ToggleAlwaysOnTop(float width, float height);
-
-        private:
-            bool TryRecoverFromNavigationModeFailure();
-
-            void OnModeChanged();
-
-            void OnCopyCommand(Platform::Object ^ parameter);
-            void OnPasteCommand(Platform::Object ^ parameter);
-
-            void SetMenuCategories();
-
-            CalculatorApp::ViewModel::Common::ViewMode m_mode;
-            Windows::Foundation::Collections::IObservableVector<CalculatorApp::ViewModel::Common::NavCategoryGroup ^> ^ m_categories;
-            Concurrency::task<void> HandleToggleAlwaysOnTop(float width, float height);
-            void SetDisplayNormalAlwaysOnTopOption();
-        };
-    }
-}
--- a/src/CalcViewModel/CalcViewModel.vcxproj
+++ b/src/CalcViewModel/CalcViewModel.vcxproj
@ -314,7 +314,6 @@
    <ResourceCompile Include="CalcViewModel.rc" PreprocessorDefinitions="%(PreprocessorDefinitions);APP_VERSION_MAJOR=$(Version.Split(`.`)[0]);APP_VERSION_MINOR=$(Version.Split(`.`)[1]);APP_VERSION_BUILD=$(Version.Split(`.`)[2]);APP_VERSION_REVISION=$(Version.Split(`.`)[3])" />
  </ItemGroup>
  <ItemGroup>
-    <ClInclude Include="ApplicationViewModel.h" />
    <ClInclude Include="Common\AppResourceProvider.h" />
    <ClInclude Include="Common\Automation\NarratorAnnouncement.h" />
    <ClInclude Include="Common\Automation\NarratorNotifier.h" />
@ -359,7 +358,6 @@
    <ClInclude Include="UnitConverterViewModel.h" />
  </ItemGroup>
  <ItemGroup>
-    <ClCompile Include="ApplicationViewModel.cpp" />
    <ClCompile Include="Common\AppResourceProvider.cpp" />
    <ClCompile Include="Common\Automation\NarratorAnnouncement.cpp" />
    <ClCompile Include="Common\Automation\NarratorNotifier.cpp" />
--- a/src/CalcViewModel/CalcViewModel.vcxproj.filters
+++ b/src/CalcViewModel/CalcViewModel.vcxproj.filters
@ -82,7 +82,6 @@
    <ClCompile Include="GraphingCalculator\GraphingSettingsViewModel.cpp">
      <Filter>GraphingCalculator</Filter>
    </ClCompile>
-    <ClCompile Include="ApplicationViewModel.cpp" />
    <ClCompile Include="DateCalculatorViewModel.cpp" />
    <ClCompile Include="HistoryItemViewModel.cpp" />
    <ClCompile Include="HistoryViewModel.cpp" />
@ -189,7 +188,6 @@
    <ClInclude Include="GraphingCalculator\VariableViewModel.h">
      <Filter>GraphingCalculator</Filter>
    </ClInclude>
-    <ClInclude Include="ApplicationViewModel.h" />
    <ClInclude Include="DateCalculatorViewModel.h" />
    <ClInclude Include="GraphingCalculatorEnums.h" />
    <ClInclude Include="HistoryItemViewModel.h" />
--- a/src/CalcViewModel/Common/NavCategory.cpp
+++ b/src/CalcViewModel/Common/NavCategory.cpp
@ -306,7 +306,7 @@ void NavCategoryStates::SetCurrentUser(Platform::String^ userId)
    CurrentUserId = userId;
 }

-IObservableVector<NavCategoryGroup ^> ^ NavCategoryStates::CreateMenuOptions()
+IVector<NavCategoryGroup ^> ^ NavCategoryStates::CreateMenuOptions()
 {
    auto menuOptions = ref new Vector<NavCategoryGroup ^>();
    menuOptions->Append(CreateCalculatorCategoryGroup());
--- a/src/CalcViewModel/Common/NavCategory.h
+++ b/src/CalcViewModel/Common/NavCategory.h
@ -146,14 +146,14 @@ namespace CalculatorApp::ViewModel
            OBSERVABLE_PROPERTY_R(Platform::String ^, Name);
            OBSERVABLE_PROPERTY_R(Platform::String ^, AutomationName);
            OBSERVABLE_PROPERTY_R(CategoryGroupType, GroupType);
-            OBSERVABLE_PROPERTY_R(Windows::Foundation::Collections::IObservableVector<NavCategory ^> ^, Categories);
+            OBSERVABLE_PROPERTY_R(Windows::Foundation::Collections::IVector<NavCategory ^> ^, Categories);
        };

        public ref class NavCategoryStates sealed
        {
        public:
            static void SetCurrentUser(Platform::String^ user);
-            static Windows::Foundation::Collections::IObservableVector<NavCategoryGroup ^> ^ CreateMenuOptions();
+            static Windows::Foundation::Collections::IVector<NavCategoryGroup ^> ^ CreateMenuOptions();
            static NavCategoryGroup ^ CreateCalculatorCategoryGroup();
            static NavCategoryGroup ^ CreateConverterCategoryGroup();

--- a/src/CalcViewModel/StandardCalculatorViewModel.h
+++ b/src/CalcViewModel/StandardCalculatorViewModel.h
@ -40,6 +40,7 @@ namespace CalculatorApp
        [Windows::UI::Xaml::Data::Bindable] public ref class StandardCalculatorViewModel sealed : public Windows::UI::Xaml::Data::INotifyPropertyChanged
        {
        public:
+            StandardCalculatorViewModel();
            void UpdateOperand(int pos, Platform::String ^ text);

            OBSERVABLE_OBJECT_CALLBACK(OnPropertyChanged);
@ -267,9 +268,11 @@ namespace CalculatorApp
            void SwitchAngleType(CalculatorApp::ViewModel::Common::NumbersAndOperatorsEnum num);
            void FtoEButtonToggled();

-            internal : void OnPaste(Platform::String ^ pastedString);
            void OnCopyCommand(Platform::Object ^ parameter);
            void OnPasteCommand(Platform::Object ^ parameter);
+            void SetCalculatorType(CalculatorApp::ViewModel::Common::ViewMode targetState);
+
+            internal : void OnPaste(Platform::String ^ pastedString);

            ButtonInfo MapCharacterToButtonId(char16 ch);

@ -284,7 +287,6 @@ namespace CalculatorApp

            Platform::String ^ GetLocalizedStringFormat(Platform::String ^ format, Platform::String ^ displayValue);
            void OnPropertyChanged(Platform::String ^ propertyname);
-            void SetCalculatorType(CalculatorApp::ViewModel::Common::ViewMode targetState);

            Platform::String ^ GetRawDisplayValue();
            void Recalculate(bool fromHistory = false);
@ -302,9 +304,6 @@ namespace CalculatorApp
                return m_CurrentAngleType;
            }

-            internal :;
-            explicit StandardCalculatorViewModel();
-
        private:
            void SetMemorizedNumbers(const std::vector<std::wstring>& memorizedNumbers);
            void UpdateProgrammerPanelDisplay();
--- a/src/CalcViewModel/UnitConverterViewModel.cpp
+++ b/src/CalcViewModel/UnitConverterViewModel.cpp
@ -152,6 +152,13 @@ UnitConverterViewModel::UnitConverterViewModel(const shared_ptr<UCM::IUnitConver
    PopulateData();
 }

+UnitConverterViewModel::UnitConverterViewModel()
+    : UnitConverterViewModel(std::make_shared<UCM::UnitConverter>(                                     //
+        std::make_shared<UnitConverterDataLoader>(ref new Windows::Globalization::GeographicRegion()), //
+        std::make_shared<CurrencyDataLoader>()))
+{
+}
+
 void UnitConverterViewModel::ResetView()
 {
    m_model->SendCommand(UCM::Command::Reset);
--- a/src/CalcViewModel/UnitConverterViewModel.h
+++ b/src/CalcViewModel/UnitConverterViewModel.h
@ -158,6 +158,11 @@ namespace CalculatorApp
            internal : UnitConverterViewModel(const std::shared_ptr<UnitConversionManager::IUnitConverter>& model);

        public:
+            UnitConverterViewModel();
+            virtual ~UnitConverterViewModel()
+            {
+            }
+
            OBSERVABLE_OBJECT_CALLBACK(OnPropertyChanged);

            OBSERVABLE_PROPERTY_R(Windows::Foundation::Collections::IObservableVector<Category ^> ^, Categories);
@ -238,15 +243,14 @@ namespace CalculatorApp
            void OnPaste(Platform::String ^ stringToPaste);
            void RefreshCurrencyRatios();
            void OnValueActivated(IActivatable ^ control);
+            void OnCopyCommand(Platform::Object ^ parameter);
+            void OnPasteCommand(Platform::Object ^ parameter);

            internal : void ResetView();
            void PopulateData();
            CalculatorApp::ViewModel::Common::NumbersAndOperatorsEnum MapCharacterToButtonId(const wchar_t ch, bool& canSendNegate);
            void DisplayPasteError();

-            void OnCopyCommand(Platform::Object ^ parameter);
-            void OnPasteCommand(Platform::Object ^ parameter);
-
            enum class CurrencyFormatterParameter
            {
                Default,
--- a/src/CalcViewModelCopyForUT/CalcViewModelCopyForUT.vcxproj
+++ b/src/CalcViewModelCopyForUT/CalcViewModelCopyForUT.vcxproj
@ -300,7 +300,6 @@
    </ClCompile>
  </ItemDefinitionGroup>
  <ItemGroup>
-    <ClInclude Include="..\CalcViewModel\ApplicationViewModel.h" />
    <ClInclude Include="..\CalcViewModel\Common\AlwaysSelectedCollectionView.h" />
    <ClInclude Include="..\CalcViewModel\Common\AppResourceProvider.h" />
    <ClInclude Include="..\CalcViewModel\Common\Automation\NarratorAnnouncement.h" />
@ -345,7 +344,6 @@
    <ClInclude Include="..\CalcViewModel\UnitConverterViewModel.h" />
  </ItemGroup>
  <ItemGroup>
-    <ClCompile Include="..\CalcViewModel\ApplicationViewModel.cpp" />
    <ClCompile Include="..\CalcViewModel\Common\AppResourceProvider.cpp" />
    <ClCompile Include="..\CalcViewModel\Common\Automation\NarratorAnnouncement.cpp" />
    <ClCompile Include="..\CalcViewModel\Common\Automation\NarratorNotifier.cpp" />
--- a/src/CalcViewModelCopyForUT/CalcViewModelCopyForUT.vcxproj.filters
+++ b/src/CalcViewModelCopyForUT/CalcViewModelCopyForUT.vcxproj.filters
@ -24,7 +24,6 @@
    <ClCompile Include="..\CalcViewModel\Common\Automation\NarratorNotifier.cpp">
      <Filter>Common\Automation</Filter>
    </ClCompile>
-    <ClCompile Include="..\CalcViewModel\ApplicationViewModel.cpp" />
    <ClCompile Include="..\CalcViewModel\DateCalculatorViewModel.cpp" />
    <ClCompile Include="..\CalcViewModel\HistoryItemViewModel.cpp" />
    <ClCompile Include="..\CalcViewModel\HistoryViewModel.cpp" />
@ -71,9 +70,6 @@
    <ClCompile Include="..\CalcViewModel\DataLoaders\CurrencyDataLoader.cpp">
      <Filter>DataLoaders</Filter>
    </ClCompile>
-    <ClCompile Include="..\CalcViewModel\DataLoaders\CurrencyHttpClient.cpp">
-      <Filter>DataLoaders</Filter>
-    </ClCompile>
    <ClCompile Include="..\CalcViewModel\DataLoaders\UnitConverterDataLoader.cpp">
      <Filter>DataLoaders</Filter>
    </ClCompile>
@ -88,6 +84,7 @@
    </ClCompile>
    <ClCompile Include="..\CalcViewModel\Common\RadixType.cpp" />
    <ClCompile Include="..\CalcViewModel\Snapshots.cpp" />
+    <ClCompile Include="DataLoaders\CurrencyHttpClient.cpp" />
  </ItemGroup>
  <ItemGroup>
    <ClInclude Include="..\CalcViewModel\Common\AppResourceProvider.h">
@ -99,7 +96,6 @@
    <ClInclude Include="..\CalcViewModel\Common\Automation\NarratorNotifier.h">
      <Filter>Common\Automation</Filter>
    </ClInclude>
-    <ClInclude Include="..\CalcViewModel\ApplicationViewModel.h" />
    <ClInclude Include="..\CalcViewModel\DateCalculatorViewModel.h" />
    <ClInclude Include="..\CalcViewModel\HistoryItemViewModel.h" />
    <ClInclude Include="..\CalcViewModel\HistoryViewModel.h" />
@ -174,9 +170,6 @@
    <ClInclude Include="..\CalcViewModel\DataLoaders\CurrencyDataLoader.h">
      <Filter>DataLoaders</Filter>
    </ClInclude>
-    <ClInclude Include="..\CalcViewModel\DataLoaders\CurrencyHttpClient.h">
-      <Filter>DataLoaders</Filter>
-    </ClInclude>
    <ClInclude Include="..\CalcViewModel\DataLoaders\UnitConverterDataConstants.h">
      <Filter>DataLoaders</Filter>
    </ClInclude>
--- a/src/Calculator.ManagedViewModels/ApplicationViewModel.cs
+++ b/src/Calculator.ManagedViewModels/ApplicationViewModel.cs
@ -0,0 +1,384 @@
+// Licensed under the MIT License.
+
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
+using System.Threading.Tasks;
+using System.Windows.Input;
+
+using Windows.Foundation;
+using Windows.Storage;
+using Windows.UI.Core;
+using Windows.UI.ViewManagement;
+using Windows.UI.Xaml;
+
+using CalculatorApp.ViewModel;
+using CalculatorApp.ViewModel.Common;
+using CalculatorApp.ViewModel.Snapshot;
+
+namespace CalculatorApp.ManagedViewModels
+{
+    public class ApplicationViewModel : INotifyPropertyChanged
+    {
+        private StandardCalculatorViewModel _calcVm;
+        private DateCalculatorViewModel _dateVm;
+        private GraphingCalculatorViewModel _graphVm;
+        private UnitConverterViewModel _unitVm;
+        private ViewMode _mode = ViewMode.None;
+        private ViewMode _previousMode = ViewMode.None;
+        private bool _isAlwaysOnTop = false;
+        private bool _displayNormalAlwaysOnTopOption;
+        private string _categoryName;
+        private IList<NavCategoryGroup> _categories = NavCategoryStates.CreateMenuOptions();
+
+        public const string WidthLocalSettingsKey = "calculatorAlwaysOnTopLastWidth";
+        public const string HeightLocalSettingsKey = "calculatorAlwaysOnTopLastHeight";
+
+        public event PropertyChangedEventHandler PropertyChanged;
+
+        public ViewMode Mode
+        {
+            get => _mode;
+            set
+            {
+                if (_mode != value)
+                {
+                    PreviousMode = _mode;
+                    _mode = value;
+                    SetDisplayNormalAlwaysOnTopOption();
+                    OnModeChanged();
+                    RaisePropertyChanged();
+                }
+            }
+        }
+
+        public ICommand CopyCommand => new RelayCommand(OnCopyCommand);
+
+        public ICommand PasteCommand => new RelayCommand(OnPasteCommand);
+
+        public Visibility ClearMemoryVisibility
+        {
+            get => NavCategory.IsCalculatorViewMode(_mode) ?
+                Visibility.Visible : Visibility.Collapsed;
+        }
+
+        public ApplicationSnapshot Snapshot
+        {
+            get
+            {
+                var snapshot = new ApplicationSnapshot();
+                snapshot.Mode = (int)_mode;
+                if (_calcVm != null)
+                {
+                    snapshot.StandardCalculator = _calcVm.Snapshot;
+                }
+                return snapshot;
+            }
+        }
+
+        public StandardCalculatorViewModel CalculatorViewModel
+        {
+            get => _calcVm;
+            set
+            {
+                if (_calcVm != value)
+                {
+                    _calcVm = value;
+                    RaisePropertyChanged();
+                }
+            }
+        }
+
+        public DateCalculatorViewModel DateCalcViewModel
+        {
+            get => _dateVm;
+            set
+            {
+                if (_dateVm != value)
+                {
+                    _dateVm = value;
+                    RaisePropertyChanged();
+                }
+            }
+        }
+
+        public GraphingCalculatorViewModel GraphingCalcViewModel
+        {
+            get => _graphVm;
+            set
+            {
+                if (_graphVm != value)
+                {
+                    _graphVm = value;
+                    RaisePropertyChanged();
+                }
+            }
+        }
+
+        public UnitConverterViewModel ConverterViewModel
+        {
+            get => _unitVm;
+            set
+            {
+                if (_unitVm != value)
+                {
+                    _unitVm = value;
+                    RaisePropertyChanged();
+                }
+            }
+        }
+
+        public ViewMode PreviousMode
+        {
+            get => _previousMode;
+            set
+            {
+                if (_previousMode != value)
+                {
+                    _previousMode = value;
+                    RaisePropertyChanged();
+                }
+            }
+        }
+
+        public bool IsAlwaysOnTop
+        {
+            get => _isAlwaysOnTop;
+            private set
+            {
+                if (_isAlwaysOnTop != value)
+                {
+                    _isAlwaysOnTop = value;
+                    RaisePropertyChanged();
+                }
+            }
+        }
+
+        // Indicates whether calculator is currently in standard mode _and_ supports CompactOverlay _and_ is not in Always-on-Top mode
+        public bool DisplayNormalAlwaysOnTopOption
+        {
+            get => _displayNormalAlwaysOnTopOption;
+            private set
+            {
+                if (_displayNormalAlwaysOnTopOption != value)
+                {
+                    _displayNormalAlwaysOnTopOption = value;
+                    RaisePropertyChanged();
+                }
+            }
+        }
+
+        public string CategoryName
+        {
+            get => _categoryName;
+            set
+            {
+                if (_categoryName != value)
+                {
+                    _categoryName = value;
+                    RaisePropertyChanged();
+                }
+            }
+        }
+
+        public IList<NavCategoryGroup> Categories
+        {
+            get => _categories;
+            set
+            {
+                if (_categories != value)
+                {
+                    _categories = value;
+                    RaisePropertyChanged();
+                }
+            }
+        }
+
+        public async Task ToggleAlwaysOnTop(float width, float height)
+        {
+            var DefaultSize = new Size(320, 394);
+            const string LaunchedSettingsKey = "calculatorAlwaysOnTopLaunched";
+            var settings = ApplicationData.Current.LocalSettings;
+            if (ApplicationView.GetForCurrentView().ViewMode == ApplicationViewMode.CompactOverlay)
+            {
+                settings.Values[WidthLocalSettingsKey] = width;
+                settings.Values[HeightLocalSettingsKey] = height;
+                bool success = await ApplicationView.GetForCurrentView().TryEnterViewModeAsync(ApplicationViewMode.Default);
+                _calcVm.HistoryVM.AreHistoryShortcutsEnabled = success;
+                _calcVm.IsAlwaysOnTop = !success;
+                IsAlwaysOnTop = !success;
+            }
+            else
+            {
+                var compactOptions = ViewModePreferences.CreateDefault(ApplicationViewMode.CompactOverlay);
+                if (!settings.Values.ContainsKey(LaunchedSettingsKey))
+                {
+                    compactOptions.CustomSize = DefaultSize;
+                    settings.Values[LaunchedSettingsKey] = true;
+                }
+                else
+                {
+                    if (settings.Values.TryGetValue(WidthLocalSettingsKey, out var oldWidth) &&
+                        settings.Values.TryGetValue(HeightLocalSettingsKey, out var oldHeight))
+                    {
+                        compactOptions.CustomSize = new Size((float)oldWidth, (float)oldHeight);
+                    }
+                    else
+                    {
+                        compactOptions.CustomSize = DefaultSize;
+                    }
+                }
+                bool success = await ApplicationView.GetForCurrentView().TryEnterViewModeAsync(ApplicationViewMode.CompactOverlay, compactOptions);
+                _calcVm.HistoryVM.AreHistoryShortcutsEnabled = !success;
+                _calcVm.IsAlwaysOnTop = success;
+                IsAlwaysOnTop = success;
+            }
+            SetDisplayNormalAlwaysOnTopOption();
+        }
+
+        public void Initialize(ViewMode mode)
+        {
+            if (!NavCategoryStates.IsValidViewMode(mode) || !NavCategoryStates.IsViewModeEnabled(mode))
+            {
+                mode = ViewMode.Standard;
+            }
+            try
+            {
+                Mode = mode;
+            }
+            catch (Exception e)
+            {
+                TraceLogger.GetInstance().LogError(mode, nameof(Initialize), e.Message);
+                if (!TryRecoverFromNavigationModeFailure())
+                {
+                    // Could not navigate to standard mode either.
+                    // Throw the original exception so we have a good stack to debug.
+                    throw;
+                }
+            }
+        }
+
+        public void RestoreFromSnapshot(ApplicationSnapshot snapshot)
+        {
+            Mode = (ViewMode)snapshot.Mode;
+            if (snapshot.StandardCalculator != null)
+            {
+                _calcVm.Snapshot = snapshot.StandardCalculator;
+            }
+        }
+
+        private void OnModeChanged()
+        {
+            Debug.Assert(NavCategoryStates.IsValidViewMode(_mode));
+            if (NavCategory.IsCalculatorViewMode(_mode))
+            {
+                if (_calcVm == null)
+                {
+                    _calcVm = new StandardCalculatorViewModel();
+                }
+                _calcVm.SetCalculatorType(_mode);
+            }
+            else if (NavCategory.IsGraphingCalculatorViewMode(_mode))
+            {
+                if (_graphVm == null)
+                {
+                    _graphVm = new GraphingCalculatorViewModel();
+                }
+            }
+            else if (NavCategory.IsDateCalculatorViewMode(_mode))
+            {
+                if (_dateVm == null)
+                {
+                    _dateVm = new DateCalculatorViewModel();
+                }
+            }
+            else if (NavCategory.IsConverterViewMode(_mode))
+            {
+                if (_unitVm == null)
+                {
+                    _unitVm = new UnitConverterViewModel();
+                }
+                _unitVm.Mode = _mode;
+            }
+
+            var resProvider = AppResourceProvider.GetInstance();
+            CategoryName = resProvider.GetResourceString(NavCategoryStates.GetNameResourceKey(_mode));
+
+            // Cast mode to an int in order to save it to app data.
+            // Save the changed mode, so that the new window launches in this mode.
+            // Don't save until after we have adjusted to the new mode, so we don't save a mode that fails to load.
+            ApplicationData.Current.LocalSettings.Values[nameof(Mode)] = NavCategoryStates.Serialize(_mode);
+
+            // Log ModeChange event when not first launch, log WindowCreated on first launch
+            if (NavCategoryStates.IsValidViewMode(_previousMode))
+            {
+                TraceLogger.GetInstance().LogModeChange(_mode);
+            }
+            else
+            {
+                TraceLogger.GetInstance().LogWindowCreated(
+                    _mode,
+                    ApplicationView.GetApplicationViewIdForWindow(CoreWindow.GetForCurrentThread()));
+            }
+            RaisePropertyChanged(nameof(ClearMemoryVisibility));
+        }
+
+        private void OnCopyCommand(object param)
+        {
+            if (NavCategory.IsConverterViewMode(_mode))
+            {
+                _unitVm.OnCopyCommand(param);
+            }
+            else if (NavCategory.IsDateCalculatorViewMode(_mode))
+            {
+                _dateVm.OnCopyCommand(param);
+            }
+            else if (NavCategory.IsCalculatorViewMode(_mode))
+            {
+                _calcVm.OnCopyCommand(param);
+            }
+        }
+
+        private void OnPasteCommand(object param)
+        {
+            if (NavCategory.IsConverterViewMode(_mode))
+            {
+                _unitVm.OnPasteCommand(param);
+            }
+            else if (NavCategory.IsCalculatorViewMode(_mode))
+            {
+                _calcVm.OnPasteCommand(param);
+            }
+        }
+
+        private void SetDisplayNormalAlwaysOnTopOption()
+        {
+            DisplayNormalAlwaysOnTopOption = _mode == ViewMode.Standard &&
+                ApplicationView.GetForCurrentView().IsViewModeSupported(ApplicationViewMode.CompactOverlay) &&
+                !_isAlwaysOnTop;
+        }
+
+        private bool TryRecoverFromNavigationModeFailure()
+        {
+            // Here we are simply trying to recover from being unable to navigate to a mode.
+            // Try falling back to standard mode and if there are *any* exceptions, we should
+            // fail because something is seriously wrong.
+            try
+            {
+                Mode = ViewMode.Standard;
+                return true;
+            }
+            catch
+            {
+                return false;
+            }
+        }
+
+        private void RaisePropertyChanged([CallerMemberName] string propertyName = null)
+        {
+            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+        }
+    }
+}
--- a/src/Calculator.ManagedViewModels/Calculator.ManagedViewModels.csproj
+++ b/src/Calculator.ManagedViewModels/Calculator.ManagedViewModels.csproj
@ -0,0 +1,150 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectGuid>{2179CFDE-CDED-4DF0-8C24-A0EF6B425771}</ProjectGuid>
+    <OutputType>Library</OutputType>
+    <AppDesignerFolder>Properties</AppDesignerFolder>
+    <RootNamespace>Calculator.ManagedViewModels</RootNamespace>
+    <AssemblyName>Calculator.ManagedViewModels</AssemblyName>
+    <DefaultLanguage>en-US</DefaultLanguage>
+    <TargetPlatformIdentifier>UAP</TargetPlatformIdentifier>
+    <TargetPlatformVersion Condition=" '$(TargetPlatformVersion)' == '' ">10.0.22000.0</TargetPlatformVersion>
+    <TargetPlatformMinVersion>10.0.17763.0</TargetPlatformMinVersion>
+    <MinimumVisualStudioVersion>14</MinimumVisualStudioVersion>
+    <FileAlignment>512</FileAlignment>
+    <ProjectTypeGuids>{A5A43C5B-DE2A-4C0C-9213-0A381AF9435A};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\Debug\</OutputPath>
+    <DefineConstants>DEBUG;TRACE;NETFX_CORE;WINDOWS_UWP</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\Release\</OutputPath>
+    <DefineConstants>TRACE;NETFX_CORE;WINDOWS_UWP</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|x86'">
+    <PlatformTarget>x86</PlatformTarget>
+    <DebugSymbols>true</DebugSymbols>
+    <OutputPath>bin\x86\Debug\</OutputPath>
+    <DefineConstants>DEBUG;TRACE;NETFX_CORE;WINDOWS_UWP</DefineConstants>
+    <NoWarn>;2008</NoWarn>
+    <DebugType>full</DebugType>
+    <UseVSHostingProcess>false</UseVSHostingProcess>
+    <ErrorReport>prompt</ErrorReport>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x86'">
+    <PlatformTarget>x86</PlatformTarget>
+    <OutputPath>bin\x86\Release\</OutputPath>
+    <DefineConstants>TRACE;NETFX_CORE;WINDOWS_UWP</DefineConstants>
+    <Optimize>true</Optimize>
+    <NoWarn>;2008</NoWarn>
+    <DebugType>pdbonly</DebugType>
+    <UseVSHostingProcess>false</UseVSHostingProcess>
+    <ErrorReport>prompt</ErrorReport>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|ARM'">
+    <PlatformTarget>ARM</PlatformTarget>
+    <DebugSymbols>true</DebugSymbols>
+    <OutputPath>bin\ARM\Debug\</OutputPath>
+    <DefineConstants>DEBUG;TRACE;NETFX_CORE;WINDOWS_UWP</DefineConstants>
+    <NoWarn>;2008</NoWarn>
+    <DebugType>full</DebugType>
+    <UseVSHostingProcess>false</UseVSHostingProcess>
+    <ErrorReport>prompt</ErrorReport>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|ARM'">
+    <PlatformTarget>ARM</PlatformTarget>
+    <OutputPath>bin\ARM\Release\</OutputPath>
+    <DefineConstants>TRACE;NETFX_CORE;WINDOWS_UWP</DefineConstants>
+    <Optimize>true</Optimize>
+    <NoWarn>;2008</NoWarn>
+    <DebugType>pdbonly</DebugType>
+    <UseVSHostingProcess>false</UseVSHostingProcess>
+    <ErrorReport>prompt</ErrorReport>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|ARM64'">
+    <PlatformTarget>ARM64</PlatformTarget>
+    <DebugSymbols>true</DebugSymbols>
+    <OutputPath>bin\ARM64\Debug\</OutputPath>
+    <DefineConstants>DEBUG;TRACE;NETFX_CORE;WINDOWS_UWP</DefineConstants>
+    <NoWarn>;2008</NoWarn>
+    <DebugType>full</DebugType>
+    <UseVSHostingProcess>false</UseVSHostingProcess>
+    <ErrorReport>prompt</ErrorReport>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|ARM64'">
+    <PlatformTarget>ARM64</PlatformTarget>
+    <OutputPath>bin\ARM64\Release\</OutputPath>
+    <DefineConstants>TRACE;NETFX_CORE;WINDOWS_UWP</DefineConstants>
+    <Optimize>true</Optimize>
+    <NoWarn>;2008</NoWarn>
+    <DebugType>pdbonly</DebugType>
+    <UseVSHostingProcess>false</UseVSHostingProcess>
+    <ErrorReport>prompt</ErrorReport>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|x64'">
+    <PlatformTarget>x64</PlatformTarget>
+    <DebugSymbols>true</DebugSymbols>
+    <OutputPath>bin\x64\Debug\</OutputPath>
+    <DefineConstants>DEBUG;TRACE;NETFX_CORE;WINDOWS_UWP</DefineConstants>
+    <NoWarn>;2008</NoWarn>
+    <DebugType>full</DebugType>
+    <UseVSHostingProcess>false</UseVSHostingProcess>
+    <ErrorReport>prompt</ErrorReport>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x64'">
+    <PlatformTarget>x64</PlatformTarget>
+    <OutputPath>bin\x64\Release\</OutputPath>
+    <DefineConstants>TRACE;NETFX_CORE;WINDOWS_UWP</DefineConstants>
+    <Optimize>true</Optimize>
+    <NoWarn>;2008</NoWarn>
+    <DebugType>pdbonly</DebugType>
+    <UseVSHostingProcess>false</UseVSHostingProcess>
+    <ErrorReport>prompt</ErrorReport>
+  </PropertyGroup>
+  <PropertyGroup>
+    <RestoreProjectStyle>PackageReference</RestoreProjectStyle>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="ApplicationViewModel.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="RelayCommand.cs" />
+    <EmbeddedResource Include="Properties\Calculator.ManagedViewModels.rd.xml" />
+  </ItemGroup>
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NETCore.UniversalWindowsPlatform">
+      <Version>6.2.14</Version>
+    </PackageReference>
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\CalcViewModel\CalcViewModel.vcxproj">
+      <Project>{812d1a7b-b8ac-49e4-8e6d-af5d59500d56}</Project>
+      <Name>CalcViewModel</Name>
+    </ProjectReference>
+  </ItemGroup>
+  <PropertyGroup Condition=" '$(VisualStudioVersion)' == '' or '$(VisualStudioVersion)' &lt; '14.0' ">
+    <VisualStudioVersion>14.0</VisualStudioVersion>
+  </PropertyGroup>
+  <Import Project="$(MSBuildExtensionsPath)\Microsoft\WindowsXaml\v$(VisualStudioVersion)\Microsoft.Windows.UI.Xaml.CSharp.targets" />
+  <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
+       Other similar extension points exist, see Microsoft.Common.targets.
+  <Target Name="BeforeBuild">
+  </Target>
+  <Target Name="AfterBuild">
+  </Target>
+  -->
+</Project>
--- a/src/Calculator.ManagedViewModels/Properties/AssemblyInfo.cs
+++ b/src/Calculator.ManagedViewModels/Properties/AssemblyInfo.cs
@ -0,0 +1,8 @@
+using System.Reflection;
+using System.Runtime.InteropServices;
+
+[assembly: AssemblyTitle("Calculator.ManagedViewModels")]
+[assembly: AssemblyCompany("Microsoft Corporation")]
+[assembly: AssemblyProduct("Microsoft Windows Calculator")]
+[assembly: AssemblyCopyright("Copyright ©  2025")]
+[assembly: ComVisible(false)]
--- a/src/Calculator.ManagedViewModels/Properties/Calculator.ManagedViewModels.rd.xml
+++ b/src/Calculator.ManagedViewModels/Properties/Calculator.ManagedViewModels.rd.xml
@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+    This file contains Runtime Directives, specifications about types your application accesses
+    through reflection and other dynamic code patterns. Runtime Directives are used to control the
+    .NET Native optimizer and ensure that it does not remove code accessed by your library. If your
+    library does not do any reflection, then you generally do not need to edit this file. However,
+    if your library reflects over types, especially types passed to it or derived from its types,
+    then you should write Runtime Directives.
+
+    The most common use of reflection in libraries is to discover information about types passed
+    to the library. Runtime Directives have three ways to express requirements on types passed to
+    your library.
+
+    1.  Parameter, GenericParameter, TypeParameter, TypeEnumerableParameter
+        Use these directives to reflect over types passed as a parameter.
+
+    2.  SubTypes
+        Use a SubTypes directive to reflect over types derived from another type.
+
+    3.  AttributeImplies
+        Use an AttributeImplies directive to indicate that your library needs to reflect over
+        types or methods decorated with an attribute.
+
+    For more information on writing Runtime Directives for libraries, please visit
+    https://go.microsoft.com/fwlink/?LinkID=391919
+-->
+<Directives xmlns="http://schemas.microsoft.com/netfx/2013/01/metadata">
+  <Library Name="Calculator.ManagedViewModels">
+
+  	<!-- add directives for your library here -->
+
+  </Library>
+</Directives>
--- a/src/Calculator.ManagedViewModels/RelayCommand.cs
+++ b/src/Calculator.ManagedViewModels/RelayCommand.cs
@ -0,0 +1,36 @@
+// Licensed under the MIT License.
+
+using System;
+using System.Windows.Input;
+
+namespace CalculatorApp.ManagedViewModels
+{
+    public class RelayCommand: ICommand
+    {
+        private readonly Action<object> _execute;
+        private readonly Func<object, bool> _canExecute;
+
+        public RelayCommand(Action<object> execute, Func<object, bool> canExecute = null)
+        {
+            _execute = execute ?? throw new ArgumentNullException(nameof(execute));
+            _canExecute = canExecute;
+        }
+
+        public event EventHandler CanExecuteChanged;
+
+        public bool CanExecute(object parameter)
+        {
+            return _canExecute == null || _canExecute(parameter);
+        }
+
+        public void Execute(object parameter)
+        {
+            _execute(parameter);
+        }
+
+        public void RaiseCanExecuteChanged()
+        {
+            CanExecuteChanged?.Invoke(this, EventArgs.Empty);
+        }
+    }
+}
--- a/src/Calculator.sln
+++ b/src/Calculator.sln
@ -29,6 +29,8 @@ Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "TraceLogging", "TraceLoggin
 EndProject
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "CalcViewModelCopyForUT", "CalcViewModelCopyForUT\CalcViewModelCopyForUT.vcxproj", "{CC9B4FA7-D746-4F52-9401-0AD1B4D6B16D}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Calculator.ManagedViewModels", "Calculator.ManagedViewModels\Calculator.ManagedViewModels.csproj", "{2179CFDE-CDED-4DF0-8C24-A0EF6B425771}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|ARM = Debug|ARM
@ -41,6 +43,30 @@ Global
 		Release|x86 = Release|x86
 	EndGlobalSection
 	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|ARM.ActiveCfg = Debug|ARM
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|ARM.Build.0 = Debug|ARM
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|ARM.Deploy.0 = Debug|ARM
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|ARM64.ActiveCfg = Debug|ARM64
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|ARM64.Build.0 = Debug|ARM64
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|ARM64.Deploy.0 = Debug|ARM64
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|x64.ActiveCfg = Debug|x64
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|x64.Build.0 = Debug|x64
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|x64.Deploy.0 = Debug|x64
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|x86.ActiveCfg = Debug|x86
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|x86.Build.0 = Debug|x86
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|x86.Deploy.0 = Debug|x86
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|ARM.ActiveCfg = Release|ARM
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|ARM.Build.0 = Release|ARM
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|ARM.Deploy.0 = Release|ARM
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|ARM64.ActiveCfg = Release|ARM64
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|ARM64.Build.0 = Release|ARM64
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|ARM64.Deploy.0 = Release|ARM64
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|x64.ActiveCfg = Release|x64
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|x64.Build.0 = Release|x64
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|x64.Deploy.0 = Release|x64
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|x86.ActiveCfg = Release|x86
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|x86.Build.0 = Release|x86
+		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|x86.Deploy.0 = Release|x86
 		{311E866D-8B93-4609-A691-265941FEE101}.Debug|ARM.ActiveCfg = Debug|ARM
 		{311E866D-8B93-4609-A691-265941FEE101}.Debug|ARM.Build.0 = Debug|ARM
 		{311E866D-8B93-4609-A691-265941FEE101}.Debug|ARM64.ActiveCfg = Debug|ARM64
@ -169,30 +195,6 @@ Global
 		{FC81FF41-02CD-4CD9-9BC5-45A1E39AC6ED}.Release|x64.Build.0 = Release|x64
 		{FC81FF41-02CD-4CD9-9BC5-45A1E39AC6ED}.Release|x86.ActiveCfg = Release|Win32
 		{FC81FF41-02CD-4CD9-9BC5-45A1E39AC6ED}.Release|x86.Build.0 = Release|Win32
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|ARM.ActiveCfg = Debug|ARM
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|ARM.Build.0 = Debug|ARM
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|ARM.Deploy.0 = Debug|ARM
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|ARM64.ActiveCfg = Debug|ARM64
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|ARM64.Build.0 = Debug|ARM64
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|ARM64.Deploy.0 = Debug|ARM64
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|x64.ActiveCfg = Debug|x64
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|x64.Build.0 = Debug|x64
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|x64.Deploy.0 = Debug|x64
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|x86.ActiveCfg = Debug|x86
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|x86.Build.0 = Debug|x86
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Debug|x86.Deploy.0 = Debug|x86
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|ARM.ActiveCfg = Release|ARM
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|ARM.Build.0 = Release|ARM
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|ARM.Deploy.0 = Release|ARM
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|ARM64.ActiveCfg = Release|ARM64
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|ARM64.Build.0 = Release|ARM64
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|ARM64.Deploy.0 = Release|ARM64
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|x64.ActiveCfg = Release|x64
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|x64.Build.0 = Release|x64
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|x64.Deploy.0 = Release|x64
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|x86.ActiveCfg = Release|x86
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|x86.Build.0 = Release|x86
-		{3B773403-B0D6-4F9A-948E-512A7A5FB315}.Release|x86.Deploy.0 = Release|x86
 		{CC9B4FA7-D746-4F52-9401-0AD1B4D6B16D}.Debug|ARM.ActiveCfg = Debug|ARM
 		{CC9B4FA7-D746-4F52-9401-0AD1B4D6B16D}.Debug|ARM.Build.0 = Debug|ARM
 		{CC9B4FA7-D746-4F52-9401-0AD1B4D6B16D}.Debug|ARM64.ActiveCfg = Debug|ARM64
@ -207,6 +209,22 @@ Global
 		{CC9B4FA7-D746-4F52-9401-0AD1B4D6B16D}.Release|x64.Build.0 = Release|x64
 		{CC9B4FA7-D746-4F52-9401-0AD1B4D6B16D}.Release|x86.ActiveCfg = Release|Win32
 		{CC9B4FA7-D746-4F52-9401-0AD1B4D6B16D}.Release|x86.Build.0 = Release|Win32
+		{2179CFDE-CDED-4DF0-8C24-A0EF6B425771}.Debug|ARM.ActiveCfg = Debug|ARM
+		{2179CFDE-CDED-4DF0-8C24-A0EF6B425771}.Debug|ARM.Build.0 = Debug|ARM
+		{2179CFDE-CDED-4DF0-8C24-A0EF6B425771}.Debug|ARM64.ActiveCfg = Debug|ARM64
+		{2179CFDE-CDED-4DF0-8C24-A0EF6B425771}.Debug|ARM64.Build.0 = Debug|ARM64
+		{2179CFDE-CDED-4DF0-8C24-A0EF6B425771}.Debug|x64.ActiveCfg = Debug|x64
+		{2179CFDE-CDED-4DF0-8C24-A0EF6B425771}.Debug|x64.Build.0 = Debug|x64
+		{2179CFDE-CDED-4DF0-8C24-A0EF6B425771}.Debug|x86.ActiveCfg = Debug|x86
+		{2179CFDE-CDED-4DF0-8C24-A0EF6B425771}.Debug|x86.Build.0 = Debug|x86
+		{2179CFDE-CDED-4DF0-8C24-A0EF6B425771}.Release|ARM.ActiveCfg = Release|ARM
+		{2179CFDE-CDED-4DF0-8C24-A0EF6B425771}.Release|ARM.Build.0 = Release|ARM
+		{2179CFDE-CDED-4DF0-8C24-A0EF6B425771}.Release|ARM64.ActiveCfg = Release|ARM64
+		{2179CFDE-CDED-4DF0-8C24-A0EF6B425771}.Release|ARM64.Build.0 = Release|ARM64
+		{2179CFDE-CDED-4DF0-8C24-A0EF6B425771}.Release|x64.ActiveCfg = Release|x64
+		{2179CFDE-CDED-4DF0-8C24-A0EF6B425771}.Release|x64.Build.0 = Release|x64
+		{2179CFDE-CDED-4DF0-8C24-A0EF6B425771}.Release|x86.ActiveCfg = Release|x86
+		{2179CFDE-CDED-4DF0-8C24-A0EF6B425771}.Release|x86.Build.0 = Release|x86
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
--- a/src/Calculator/Calculator.csproj
+++ b/src/Calculator/Calculator.csproj
@ -806,6 +806,10 @@
    </PackageReference>
  </ItemGroup>
  <ItemGroup>
+    <ProjectReference Include="..\Calculator.ManagedViewModels\Calculator.ManagedViewModels.csproj">
+      <Project>{2179cfde-cded-4df0-8c24-a0ef6b425771}</Project>
+      <Name>Calculator.ManagedViewModels</Name>
+    </ProjectReference>
    <ProjectReference Include="..\CalcViewModel\CalcViewModel.vcxproj">
      <Project>{812d1a7b-b8ac-49e4-8e6d-af5d59500d56}</Project>
      <Name>CalcViewModel</Name>
--- a/src/Calculator/Common/KeyboardShortcutManager.cs
+++ b/src/Calculator/Common/KeyboardShortcutManager.cs
@ -1,7 +1,7 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.

-using CalculatorApp.ViewModel;
+using CalculatorApp.ManagedViewModels;
 using CalculatorApp.ViewModel.Common;

 using System;
--- a/src/Calculator/Views/MainPage.xaml.cs
+++ b/src/Calculator/Views/MainPage.xaml.cs
@ -19,7 +19,7 @@ using Microsoft.UI.Xaml.Controls;
 using CalculatorApp.Common;
 using CalculatorApp.Converters;
 using CalculatorApp.JsonUtils;
-using CalculatorApp.ViewModel;
+using CalculatorApp.ManagedViewModels;
 using CalculatorApp.ViewModel.Common;
 using CalculatorApp.ViewModel.Common.Automation;

@ -159,9 +159,9 @@ namespace CalculatorApp
        {
            var initialMode = ViewMode.Standard;
            var localSettings = ApplicationData.Current.LocalSettings;
-            if (localSettings.Values.ContainsKey(ApplicationViewModel.ModePropertyName))
+            if (localSettings.Values.ContainsKey(nameof(ApplicationViewModel.Mode)))
            {
-                initialMode = NavCategoryStates.Deserialize(localSettings.Values[ApplicationViewModel.ModePropertyName]);
+                initialMode = NavCategoryStates.Deserialize(localSettings.Values[nameof(ApplicationViewModel.Mode)]);
            }

            if (e.Parameter == null)
@ -202,12 +202,6 @@ namespace CalculatorApp
        private void InitializeNavViewCategoriesSource()
        {
            NavViewCategoriesSource = ExpandNavViewCategoryGroups(Model.Categories);
-            Model.Categories.VectorChanged += (sender, args) =>
-            {
-                NavViewCategoriesSource.Clear();
-                NavViewCategoriesSource = ExpandNavViewCategoryGroups(Model.Categories);
-            };
-
            _ = Window.Current.Dispatcher.RunAsync(CoreDispatcherPriority.Low, () =>
            {
                var graphCategory = (NavCategory)NavViewCategoriesSource.Find(x =>
@ -258,7 +252,7 @@ namespace CalculatorApp
        private void OnAppPropertyChanged(object sender, PropertyChangedEventArgs e)
        {
            string propertyName = e.PropertyName;
-            if (propertyName == ApplicationViewModel.ModePropertyName)
+            if (propertyName == nameof(ApplicationViewModel.Mode))
            {
                ViewMode newValue = Model.Mode;
                ViewMode previousMode = Model.PreviousMode;
@ -324,7 +318,7 @@ namespace CalculatorApp
                UpdateViewState();
                SetDefaultFocus();
            }
-            else if (propertyName == ApplicationViewModel.CategoryNamePropertyName)
+            else if (propertyName == nameof(ApplicationViewModel.CategoryName))
            {
                SetHeaderAutomationName();
                AnnounceCategoryName();
@ -541,8 +535,8 @@ namespace CalculatorApp
            if (Model.IsAlwaysOnTop)
            {
                ApplicationDataContainer localSettings = ApplicationData.Current.LocalSettings;
-                localSettings.Values[ApplicationViewModel.WidthLocalSettings] = ActualWidth;
-                localSettings.Values[ApplicationViewModel.HeightLocalSettings] = ActualHeight;
+                localSettings.Values[ApplicationViewModel.WidthLocalSettingsKey] = ActualWidth;
+                localSettings.Values[ApplicationViewModel.HeightLocalSettingsKey] = ActualHeight;
            }
        }

--- a/src/CalculatorUnitTests/NavCategoryUnitTests.cpp
+++ b/src/CalculatorUnitTests/NavCategoryUnitTests.cpp
@ -98,14 +98,14 @@ namespace CalculatorUnitTests
    public:
        TEST_METHOD(CreateNavCategoryGroup)
        {
-            IObservableVector<NavCategoryGroup ^> ^ menuOptions = NavCategoryStates::CreateMenuOptions();
+            IVector<NavCategoryGroup ^> ^ menuOptions = NavCategoryStates::CreateMenuOptions();

            VERIFY_ARE_EQUAL(2, menuOptions->Size);

            NavCategoryGroup ^ calculatorGroup = menuOptions->GetAt(0);
            VERIFY_ARE_EQUAL(CategoryGroupType::Calculator, calculatorGroup->GroupType);

-            IObservableVector<NavCategory ^> ^ calculatorCategories = calculatorGroup->Categories;
+            IVector<NavCategory ^> ^ calculatorCategories = calculatorGroup->Categories;
            ValidateNavCategory(calculatorCategories, 0u, ViewMode::Standard);
            ValidateNavCategory(calculatorCategories, 1u, ViewMode::Scientific);
            ValidateNavCategory(calculatorCategories, 2u, ViewMode::Graphing);
@ -116,7 +116,7 @@ namespace CalculatorUnitTests
            NavCategoryGroup ^ converterGroup = menuOptions->GetAt(1);
            VERIFY_ARE_EQUAL(CategoryGroupType::Converter, converterGroup->GroupType);

-            IObservableVector<NavCategory ^> ^ converterCategories = converterGroup->Categories;
+            IVector<NavCategory ^> ^ converterCategories = converterGroup->Categories;
            VERIFY_ARE_EQUAL(13, converterCategories->Size);
            ValidateNavCategory(converterCategories, 0u, ViewMode::Currency);
            ValidateNavCategory(converterCategories, 1u, ViewMode::Volume);
@ -134,7 +134,7 @@ namespace CalculatorUnitTests
        }

    private:
-        void ValidateNavCategory(IObservableVector<NavCategory ^> ^ categories, unsigned int index, ViewMode expectedMode)
+        void ValidateNavCategory(IVector<NavCategory ^> ^ categories, unsigned int index, ViewMode expectedMode)
        {
            VERIFY_IS_LESS_THAN(0u, categories->Size);
            VERIFY_IS_GREATER_THAN(categories->Size, index);