Settings Back Button For Nested Pages

When navigating to a nested page e.g. Advanced Options, the Back Button appears for the navigation list now, this follows windows UI, see Windows Settings for a example

Author: Techypanda

src/cascadia/TerminalSettingsEditor/MainPage.cpp

@@ -150,6 +150,7 @@ namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
         Automation::AutomationProperties::SetHelpText(OpenJsonNavItem(), RS_(L"Nav_OpenJSON/[using:Windows.UI.Xaml.Controls]ToolTipService/ToolTip"));
 
         _breadcrumbs = single_threaded_observable_vector<IInspectable>();
+        _breadcrumbs.VectorChanged({ this, &MainPage::_OnBreadcrumbsChange });
     }
 
     // Method Description:
@@ -683,33 +684,55 @@ namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
         _settingsClone.WriteSettingsToDisk();
     }
 
+    void MainPage::BackButton_Click(winrt::Microsoft::UI::Xaml::Controls::NavigationView const& /*args*/, winrt::Microsoft::UI::Xaml::Controls::NavigationViewBackRequestedEventArgs const& /*sender*/)
+    {
+        if (_breadcrumbs.Size() < 2)
+        {
+            return;
+        }
+        const auto previousBreadcrumb = _breadcrumbs.GetAt(_breadcrumbs.Size() - 2).try_as<Breadcrumb>();
+        _NavigatePreviousPageForBreadcrumb(previousBreadcrumb);
+    }
+
     void MainPage::ResetButton_Click(const IInspectable& /*sender*/, const RoutedEventArgs& /*args*/)
     {
         UpdateSettings(_settingsSource);
     }
 
+    void MainPage::_NavigatePreviousPageForBreadcrumb(const winrt::impl::com_ref<Breadcrumb>& breadcrumb)
+    {
+        const auto tag = breadcrumb->Tag();
+        const auto subPage = breadcrumb->SubPage();
+        if (const auto profileViewModel = tag.try_as<ProfileViewModel>())
+        {
+            _Navigate(*profileViewModel, subPage);
+        }
+        else if (const auto ntmEntryViewModel = tag.try_as<NewTabMenuEntryViewModel>())
+        {
+            _Navigate(*ntmEntryViewModel, subPage);
+        }
+        else if (const auto extPkgViewModel = tag.try_as<ExtensionPackageViewModel>())
+        {
+            _Navigate(*extPkgViewModel, subPage);
+        }
+        else
+        {
+            _Navigate(tag.as<hstring>(), subPage);
+        }
+    }
+
+    void MainPage::_OnBreadcrumbsChange(IObservableVector<winrt::Windows::Foundation::IInspectable> const& vect, IVectorChangedEventArgs const& /*args*/)
+    {
+        const auto settingsNav = SettingsNav();
+        settingsNav.IsBackButtonVisible(vect.Size() > 1 ? winrt::Microsoft::UI::Xaml::Controls::NavigationViewBackButtonVisible::Visible : winrt::Microsoft::UI::Xaml::Controls::NavigationViewBackButtonVisible::Collapsed);
+        settingsNav.IsBackEnabled(vect.Size() > 1 ? true : false);
+    }
+
     void MainPage::BreadcrumbBar_ItemClicked(const Microsoft::UI::Xaml::Controls::BreadcrumbBar& /*sender*/, const Microsoft::UI::Xaml::Controls::BreadcrumbBarItemClickedEventArgs& args)
     {
         if (gsl::narrow_cast<uint32_t>(args.Index()) < (_breadcrumbs.Size() - 1))
         {
-            const auto tag = args.Item().as<Breadcrumb>()->Tag();
-            const auto subPage = args.Item().as<Breadcrumb>()->SubPage();
-            if (const auto profileViewModel = tag.try_as<ProfileViewModel>())
-            {
-                _Navigate(*profileViewModel, subPage);
-            }
-            else if (const auto ntmEntryViewModel = tag.try_as<NewTabMenuEntryViewModel>())
-            {
-                _Navigate(*ntmEntryViewModel, subPage);
-            }
-            else if (const auto extPkgViewModel = tag.try_as<ExtensionPackageViewModel>())
-            {
-                _Navigate(*extPkgViewModel, subPage);
-            }
-            else
-            {
-                _Navigate(tag.as<hstring>(), subPage);
-            }
+            _NavigatePreviousPageForBreadcrumb(args.Item().as<Breadcrumb>());
         }
     }
 

src/cascadia/TerminalSettingsEditor/MainPage.h

@@ -33,6 +33,7 @@ namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
         void SettingsNav_Loaded(const Windows::Foundation::IInspectable& sender, const Windows::UI::Xaml::RoutedEventArgs& args);
         void SettingsNav_ItemInvoked(const Microsoft::UI::Xaml::Controls::NavigationView& sender, const Microsoft::UI::Xaml::Controls::NavigationViewItemInvokedEventArgs& args);
         void SaveButton_Click(const Windows::Foundation::IInspectable& sender, const Windows::UI::Xaml::RoutedEventArgs& args);
+        void BackButton_Click(winrt::Microsoft::UI::Xaml::Controls::NavigationView const& args, winrt::Microsoft::UI::Xaml::Controls::NavigationViewBackRequestedEventArgs const& sender);
         void ResetButton_Click(const Windows::Foundation::IInspectable& sender, const Windows::UI::Xaml::RoutedEventArgs& args);
         void BreadcrumbBar_ItemClicked(const Microsoft::UI::Xaml::Controls::BreadcrumbBar& sender, const Microsoft::UI::Xaml::Controls::BreadcrumbBarItemClickedEventArgs& args);
 
@@ -72,6 +73,8 @@ namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
         void _Navigate(const Editor::ExtensionPackageViewModel& extPkgVM, BreadcrumbSubPage subPage);
         void _NavigateToProfileHandler(const IInspectable& sender, winrt::guid profileGuid);
         void _NavigateToColorSchemeHandler(const IInspectable& sender, const IInspectable& args);
+        void _NavigatePreviousPageForBreadcrumb(const winrt::impl::com_ref<Breadcrumb>& breadcrumb);
+        void _OnBreadcrumbsChange(Windows::Foundation::Collections::IObservableVector<winrt::Windows::Foundation::IInspectable> const& vect, Windows::Foundation::Collections::IVectorChangedEventArgs const& args);
 
         void _UpdateBackgroundForMica();
         void _MoveXamlParsedNavItemsIntoItemSource();

src/cascadia/TerminalSettingsEditor/MainPage.xaml

@@ -66,6 +66,7 @@
 
     <muxc:NavigationView x:Name="SettingsNav"
                          Background="{ThemeResource SettingsPageBackground}"
+                         BackRequested="BackButton_Click"
                          IsBackButtonVisible="Collapsed"
                          IsSettingsVisible="False"
                          ItemInvoked="SettingsNav_ItemInvoked"