resolve some warnings

src/Calculator/App.xaml.cs

@@ -499,9 +499,6 @@ namespace CalculatorApp
         private Dictionary<int, WindowFrameService> m_secondaryWindows = new Dictionary<int, WindowFrameService>();
         private int m_mainViewId;
         private bool m_preLaunched;
-
-        // CSHARP_MIGRATION: TODO: check whether or not this field is in use.
-        private Windows.UI.Xaml.Controls.Primitives.Popup m_aboutPopup;
     }
 }
 

src/Calculator/Common/AlwaysSelectedCollectionView.cs

@@ -223,8 +223,12 @@ namespace CalculatorApp
             }
 
             public event EventHandler<object> CurrentChanged;
-            public event CurrentChangingEventHandler CurrentChanging; // CSHARP_MIGRATION: TODO: check why this member is never being used.
             public event VectorChangedEventHandler<object> VectorChanged;
+            public event CurrentChangingEventHandler CurrentChanging
+            {
+                add => throw new NotImplementedException();
+                remove => throw new NotImplementedException();
+            }
 
             IList m_source;
             int m_currentPosition;

src/Calculator/Controls/OverflowTextBlock.cs

@@ -38,7 +38,6 @@ namespace CalculatorApp
             public OverflowTextBlock()
             {
                 m_isAccessibilityViewControl = false;
-                m_ignoreViewChanged = false;
                 m_expressionContent = null;
                 m_itemsControl = null;
                 m_expressionContainer = null;
@@ -322,7 +321,6 @@ namespace CalculatorApp
             private const double SCROLL_RATIO = 0.7;
 
             private bool m_isAccessibilityViewControl;
-            private bool m_ignoreViewChanged;
             private Windows.UI.Xaml.FrameworkElement m_expressionContent;
             private Windows.UI.Xaml.Controls.ItemsControl m_itemsControl;
             private Windows.UI.Xaml.Controls.ScrollViewer m_expressionContainer;

src/Calculator/EquationStylePanelControl.xaml.cs

@@ -107,14 +107,11 @@ namespace CalculatorApp
             {
                 case EquationLineStyle.Dot:
                     return resourceLoader.GetResourceString("dotLineStyleAutomationName");
-                    break;
                 case EquationLineStyle.Dash:
                     return resourceLoader.GetResourceString("dashLineStyleAutomationName");
-                    break;
                 case EquationLineStyle.Solid:
                 default:
                     return resourceLoader.GetResourceString("solidLineStyleAutomationName");
-                    break;
             }
         }
 

src/Calculator/Views/Calculator.xaml.cs

@@ -629,7 +629,6 @@ namespace CalculatorApp
             }
         }
 
-        private Windows.UI.Xaml.Controls.ListView m_tokenList;
         private Windows.UI.Xaml.Controls.MenuFlyout m_displayFlyout;
         private bool m_doAnimate;
         private bool m_resultAnimate;
@@ -646,7 +645,6 @@ namespace CalculatorApp
         private string m_dockPanelMemoryList;
 
         private Windows.UI.Xaml.Controls.PivotItem m_pivotItem;
-        private bool m_IsDigit = false;
         private Memory m_memory;
 
         private void HistoryFlyout_Opened(object sender, object args)

src/Calculator/Views/CalculatorProgrammerRadixOperators.xaml.cs

@@ -34,7 +34,20 @@ namespace CalculatorApp
             get { return (StandardCalculatorViewModel)this.DataContext; }
         }
 
-        public bool IsErrorVisualState { get; set; }
+        public bool IsErrorVisualState
+        {
+            get => m_isErrorVisualState;
+            set
+            {
+                if(m_isErrorVisualState != value)
+                {
+                    m_isErrorVisualState = value;
+                    string newState = m_isErrorVisualState ? "ErrorLayout" : "NoErrorLayout";
+                    VisualStateManager.GoToState(this, newState, false);
+                    NumberPad.IsErrorVisualState = m_isErrorVisualState;
+                }
+            }
+        }
 
         public string ParenthesisCountToString(uint count)
         {

src/Calculator/Views/CalculatorScientificAngleButtons.xaml.cs

@@ -60,7 +60,19 @@ namespace CalculatorApp
         }
         private System.Windows.Input.ICommand donotuse_ButtonPressed;
 
-        public bool IsErrorVisualState { get; set; }
+        public bool IsErrorVisualState
+        {
+            get => m_isErrorVisualState;
+            set
+            {
+                if(m_isErrorVisualState != value)
+                {
+                    m_isErrorVisualState = value;
+                    string newState = m_isErrorVisualState ? "ErrorFlyout" : "NoErrorFlyout";
+                    VisualStateManager.GoToState(this, newState, false);
+                }
+            }
+        }
 
         private void OnAngleButtonPressed(object commandParameter)
         {

src/Calculator/Views/CalculatorScientificOperators.xaml.cs

@@ -26,7 +26,6 @@ using Windows.UI.Xaml.Data;
 using Windows.UI.Xaml.Input;
 using Windows.UI.Xaml.Media;
 using Windows.UI.Xaml.Navigation;
-using Windows.UI.Core;
 
 namespace CalculatorApp
 {

src/Calculator/Views/HistoryList.xaml.cs

@@ -43,9 +43,6 @@ namespace CalculatorApp
         public static readonly DependencyProperty RowHeightProperty =
             DependencyProperty.Register(nameof(RowHeight), typeof(Windows.UI.Xaml.GridLength), typeof(HistoryList), new PropertyMetadata(default(Windows.UI.Xaml.GridLength)));
 
-        private Windows.Foundation.Rect m_visibleBounds;
-        private Windows.Foundation.Rect m_coreBounds;
-
         private void ListView_ItemClick(object sender, ItemClickEventArgs e)
         {
             HistoryViewModel historyVM = (DataContext as HistoryViewModel);

src/Calculator/Views/Memory.xaml.cs

@@ -49,8 +49,6 @@ namespace CalculatorApp
             }
         }
 
-        private Windows.Foundation.Rect m_visibleBounds;
-        private Windows.Foundation.Rect m_coreBounds;
         private bool m_isErrorVisualState = false;
 
         private void MemoryListItemClick(object sender, ItemClickEventArgs e)

src/Calculator/Views/UnitConverter.xaml.cs

@@ -48,7 +48,7 @@ namespace CalculatorApp
             get => this.m_FlowDirectionHorizontalAlignment;
         }
 
-        private Windows.UI.Xaml.HorizontalAlignment m_FlowDirectionHorizontalAlignment;
+        private Windows.UI.Xaml.HorizontalAlignment m_FlowDirectionHorizontalAlignment = default(HorizontalAlignment);
 
         public void AnimateConverter()
         {
@@ -373,11 +373,11 @@ namespace CalculatorApp
         }
 
         private static Lazy<UISettings> uiSettings = new Lazy<UISettings>(true);
-        private Windows.UI.Xaml.FlowDirection m_layoutDirection;
+        private Windows.UI.Xaml.FlowDirection m_layoutDirection = default(FlowDirection);
-        private Windows.UI.Xaml.Controls.MenuFlyout m_resultsFlyout;
+        private Windows.UI.Xaml.Controls.MenuFlyout m_resultsFlyout = default(MenuFlyout);
 
-        private string m_chargesMayApplyText;
+        private string m_chargesMayApplyText = string.Empty;
-        private string m_failedToRefreshText;
+        private string m_failedToRefreshText = string.Empty;
 
         private bool m_meteredConnectionOverride;