Make History and Memory list items context menu accessible using keyboard (#432)

* Move History and Memory context menus to ListViewItemContainer so users can open them with keyboards

* replace static_cast by dynamic_cast

src/Calculator/Views/HistoryList.xaml

@@ -49,7 +49,7 @@
                                 Invoked="OnDeleteSwipeInvoked"/>
             </muxc:SwipeItems>
 
-            <MenuFlyout x:Key="HistoryContextMenu">
+            <MenuFlyout x:Name="HistoryContextMenu">
                 <MenuFlyoutItem x:Uid="DeleteHistoryMenuItem"
                                 Click="OnDeleteMenuItemClicked"
                                 Icon="Delete"/>
@@ -57,9 +57,7 @@
 
             <DataTemplate x:Key="HistoryItemTemplate" x:DataType="model:HistoryItemViewModel">
                 <muxc:SwipeControl RightItems="{StaticResource HistorySwipeItems}">
-                    <StackPanel Margin="0,6,4,6"
+                    <StackPanel Margin="0,6,4,6" Background="Transparent">
-                                Background="Transparent"
-                                ContextFlyout="{StaticResource HistoryContextMenu}">
                         <TextBlock x:Name="ExprTextBlock"
                                    Margin="0,0,0,4"
                                    HorizontalAlignment="Right"
@@ -85,6 +83,7 @@
                    BasedOn="{StaticResource HistoryMemoryItemContainerStyle}"
                    TargetType="ListViewItem">
                 <Setter Property="Margin" Value="0,0,0,20"/>
+                <Setter Property="ContextFlyout" Value="{StaticResource HistoryContextMenu}"/>
             </Style>
         </ResourceDictionary>
     </UserControl.Resources>

src/Calculator/Views/HistoryList.xaml.cpp

@@ -42,11 +42,11 @@ HistoryList::HistoryList()
 
 void HistoryList::ListView_ItemClick(_In_ Object ^ sender, _In_ ItemClickEventArgs ^ e)
 {
-    HistoryViewModel ^ historyVM = static_cast<HistoryViewModel ^>(this->DataContext);
+    HistoryViewModel^ historyVM = dynamic_cast<HistoryViewModel ^>(this->DataContext);
-    HistoryItemViewModel ^ clickedItem = safe_cast<HistoryItemViewModel ^>(e->ClickedItem);
+    HistoryItemViewModel^ clickedItem = dynamic_cast<HistoryItemViewModel ^>(e->ClickedItem);
 
     // When the user clears the history list in the overlay view and presses enter, the clickedItem is nullptr
-    if (clickedItem != nullptr)
+    if (clickedItem != nullptr && historyVM != nullptr)
     {
         historyVM->ShowItem(clickedItem);
     }
@@ -54,16 +54,21 @@ void HistoryList::ListView_ItemClick(_In_ Object ^ sender, _In_ ItemClickEventAr
 
 void HistoryList::OnDeleteMenuItemClicked(_In_ Object ^ sender, _In_ RoutedEventArgs ^ e)
 {
-    auto clickedItem = safe_cast<HistoryItemViewModel ^>(safe_cast<FrameworkElement ^>(sender)->DataContext);
+    auto listViewItem = HistoryContextMenu->Target;
-
+    auto itemViewModel = dynamic_cast<HistoryItemViewModel ^>(HistoryListView->ItemFromContainer(listViewItem));
-    Model->DeleteItem(clickedItem);
+    if (itemViewModel != nullptr)
+    {
+        Model->DeleteItem(itemViewModel);
+    }
 }
 
 void HistoryList::OnDeleteSwipeInvoked(_In_ MUXC::SwipeItem ^ sender, _In_ MUXC::SwipeItemInvokedEventArgs ^ e)
 {
-    auto swipedItem = safe_cast<HistoryItemViewModel ^>(e->SwipeControl->DataContext);
+    auto swipedItem = dynamic_cast<HistoryItemViewModel ^>(e->SwipeControl->DataContext);
-
+    if (swipedItem != nullptr)
-    Model->DeleteItem(swipedItem);
+    {
+        Model->DeleteItem(swipedItem);
+    }
 }
 
 void HistoryList::ScrollToBottom()

src/Calculator/Views/Memory.xaml

@@ -17,7 +17,7 @@
         <converters:BooleanToVisibilityNegationConverter x:Key="BooleanToVisibilityNegationConverter"/>
         <converters:BooleanNegationConverter x:Key="BooleanNegationConverter"/>
 
-        <MenuFlyout x:Key="MemoryContextMenu">
+        <MenuFlyout x:Name="MemoryContextMenu">
             <MenuFlyoutItem x:Uid="ClearMemoryMenuItem" Click="OnClearMenuItemClicked">
                 <MenuFlyoutItem.Icon>
                     <FontIcon FontFamily="{StaticResource CalculatorFontFamily}" Glyph="&#xf754;"/>
@@ -42,6 +42,7 @@
                BasedOn="{StaticResource HistoryMemoryItemContainerStyle}"
                TargetType="ListViewItem">
             <Setter Property="Margin" Value="0,0,0,8"/>
+            <Setter Property="ContextFlyout" Value="{StaticResource MemoryContextMenu}"/>
         </Style>
     </UserControl.Resources>
 
@@ -103,8 +104,6 @@
             <ListView x:Name="MemoryListView"
                       Padding="0,12,0,0"
                       HorizontalAlignment="Stretch"
-                      ContextCanceled="OnContextCanceled"
-                      ContextRequested="OnContextRequested"
                       IsItemClickEnabled="true"
                       ItemClick="MemoryListItemClick"
                       ItemContainerStyle="{ThemeResource MemoryItemContainerStyle}"

src/Calculator/Views/Memory.xaml.cpp

@@ -39,7 +39,6 @@ Memory::Memory()
     : m_isErrorVisualState(false)
 {
     InitializeComponent();
-    m_memoryItemFlyout = safe_cast<MenuFlyout ^>(Resources->Lookup("MemoryContextMenu"));
 
     MemoryPaneEmpty->FlowDirection = LocalizationService::GetInstance()->GetFlowDirection();
 }
@@ -56,53 +55,31 @@ void Memory::MemoryListItemClick(_In_ Object ^ sender, _In_ ItemClickEventArgs ^
     }
 }
 
-void Memory::OnContextRequested(Windows::UI::Xaml::UIElement ^ sender, Windows::UI::Xaml::Input::ContextRequestedEventArgs ^ e)
-{
-    // Walk up the tree to find the ListViewItem.
-    // There may not be one if the click wasn't on an item.
-    auto requestedElement = safe_cast<FrameworkElement ^>(e->OriginalSource);
-    while ((requestedElement != sender) && !dynamic_cast<ListViewItem ^>(requestedElement))
-    {
-        requestedElement = safe_cast<FrameworkElement ^>(VisualTreeHelper::GetParent(requestedElement));
-    }
-
-    if (requestedElement != sender)
-    {
-        // The context menu request was for a ListViewItem.
-        auto memorySlot = safe_cast<MemoryItemViewModel ^>(MemoryListView->ItemFromContainer(requestedElement));
-        Point point;
-        if (e->TryGetPosition(requestedElement, &point))
-        {
-            m_memoryItemFlyout->ShowAt(requestedElement, point);
-        }
-        else
-        {
-            // Not invoked via pointer, so let XAML choose a default location.
-            m_memoryItemFlyout->ShowAt(requestedElement);
-        }
-
-        e->Handled = true;
-    }
-}
-
-void Memory::OnContextCanceled(Windows::UI::Xaml::UIElement ^ sender, Windows::UI::Xaml::RoutedEventArgs ^ e)
-{
-    m_memoryItemFlyout->Hide();
-}
-
 void Memory::OnClearMenuItemClicked(_In_ Object ^ sender, _In_ RoutedEventArgs ^ e)
 {
-    GetMemoryItemForCurrentFlyout()->Clear();
+    auto memoryItem = GetMemoryItemForCurrentFlyout();
+    if (memoryItem != nullptr)
+    {
+        memoryItem->Clear();
+    }
 }
 
 void Memory::OnMemoryAddMenuItemClicked(_In_ Object ^ sender, _In_ RoutedEventArgs ^ e)
 {
-    GetMemoryItemForCurrentFlyout()->MemoryAdd();
+    auto memoryItem = GetMemoryItemForCurrentFlyout();
+    if (memoryItem != nullptr)
+    {
+        memoryItem->MemoryAdd();
+    }
 }
 
 void Memory::OnMemorySubtractMenuItemClicked(_In_ Object ^ sender, _In_ RoutedEventArgs ^ e)
 {
-    GetMemoryItemForCurrentFlyout()->MemorySubtract();
+    auto memoryItem = GetMemoryItemForCurrentFlyout();
+    if (memoryItem != nullptr)
+    {
+        memoryItem->MemorySubtract();
+    }
 }
 
 bool Memory::IsErrorVisualState::get()
@@ -122,7 +99,6 @@ void Memory::IsErrorVisualState::set(bool value)
 
 MemoryItemViewModel ^ Memory::GetMemoryItemForCurrentFlyout()
 {
-    auto listViewItem = m_memoryItemFlyout->Target;
+    auto listViewItem = MemoryContextMenu->Target;
-
+    return dynamic_cast<MemoryItemViewModel ^>(MemoryListView->ItemFromContainer(listViewItem));
-    return safe_cast<MemoryItemViewModel ^>(MemoryListView->ItemFromContainer(listViewItem));
 }

src/Calculator/Views/Memory.xaml.h

@@ -36,14 +36,11 @@ namespace CalculatorApp
         }
 
     private:
-        Windows::UI::Xaml::Controls::MenuFlyout ^ m_memoryItemFlyout;
         Windows::Foundation::Rect m_visibleBounds;
         Windows::Foundation::Rect m_coreBounds;
         bool m_isErrorVisualState;
 
         void MemoryListItemClick(_In_ Platform::Object ^ sender, _In_ Windows::UI::Xaml::Controls::ItemClickEventArgs ^ e);
-        void OnContextRequested(Windows::UI::Xaml::UIElement ^ sender, Windows::UI::Xaml::Input::ContextRequestedEventArgs ^ e);
-        void OnContextCanceled(Windows::UI::Xaml::UIElement ^ sender, Windows::UI::Xaml::RoutedEventArgs ^ e);
         void OnClearMenuItemClicked(_In_ Platform::Object ^ sender, _In_ Windows::UI::Xaml::RoutedEventArgs ^ e);
         void OnMemoryAddMenuItemClicked(_In_ Platform::Object ^ sender, _In_ Windows::UI::Xaml::RoutedEventArgs ^ e);
         void OnMemorySubtractMenuItemClicked(_In_ Platform::Object ^ sender, _In_ Windows::UI::Xaml::RoutedEventArgs ^ e);