NumberBox: Fix header foreground color not being properly updated when NumberBox is disabled.

dev/NumberBox/APITests/NumberBoxTests.cs

@@ -85,6 +85,43 @@ public void VerifyNumberBoxCornerRadius()
             });
         }
 
+        [TestMethod]
+        public void VerifyIsEnabledChangeUpdatesVisualState()
+        {
+            var numberBox = SetupNumberBox();
+
+            VisualStateGroup commonStatesGroup = null;
+            RunOnUIThread.Execute(() =>
+            {
+                // Check 1: Set IsEnabled to true.
+                numberBox.IsEnabled = true;
+                Content.UpdateLayout();
+
+                var numberBoxLayoutRoot = (FrameworkElement)VisualTreeHelper.GetChild(numberBox, 0);
+                commonStatesGroup = VisualStateManager.GetVisualStateGroups(numberBoxLayoutRoot).First(vsg => vsg.Name.Equals("CommonStates"));
+
+                Verify.AreEqual("Normal", commonStatesGroup.CurrentState.Name);
+
+                // Check 2: Set IsEnabled to false.
+                numberBox.IsEnabled = false;
+            });
+            IdleSynchronizer.Wait();
+
+            RunOnUIThread.Execute(() =>
+            {
+                Verify.AreEqual("Disabled", commonStatesGroup.CurrentState.Name);
+
+                // Check 3: Set IsEnabled back to true.
+                numberBox.IsEnabled = true;
+            });
+            IdleSynchronizer.Wait();
+
+            RunOnUIThread.Execute(() =>
+            {
+                Verify.AreEqual("Normal", commonStatesGroup.CurrentState.Name);
+            });
+        }
+
         private NumberBox SetupNumberBox()
         {
             NumberBox numberBox = null;

dev/NumberBox/NumberBox.cpp

@@ -198,12 +198,16 @@ void NumberBox::OnApplyTemplate()
         m_popupUpButtonClickRevoker = popupSpinUp.Click(winrt::auto_revoke, { this, &NumberBox::OnSpinUpClick });
     }
 
+    m_isEnabledChangedRevoker = IsEnabledChanged(winrt::auto_revoke, { this,  &NumberBox::OnIsEnabledChanged });
+
     // .NET rounds to 12 significant digits when displaying doubles, so we will do the same.
     m_displayRounder.SignificantDigits(12);
 
     UpdateSpinButtonPlacement();
     UpdateSpinButtonEnabled();
 
+    UpdateVisualStateForIsEnabledChange();
+
     if (ReadLocalValue(s_ValueProperty) == winrt::DependencyProperty::UnsetValue()
         && ReadLocalValue(s_TextProperty) != winrt::DependencyProperty::UnsetValue())
     {
@@ -216,7 +220,7 @@ void NumberBox::OnApplyTemplate()
     }
 }
 
-void NumberBox::OnCornerRadiusPropertyChanged(const winrt::DependencyObject& /*sender*/, const winrt::DependencyProperty& /*args*/)
+void NumberBox::OnCornerRadiusPropertyChanged(const winrt::DependencyObject&, const winrt::DependencyProperty&)
 {
     if (this->SpinButtonPlacementMode() == winrt::NumberBoxSpinButtonPlacementMode::Inline)
     {
@@ -338,6 +342,16 @@ void NumberBox::OnValidationModePropertyChanged(const winrt::DependencyPropertyC
     UpdateSpinButtonEnabled();
 }
 
+void NumberBox::OnIsEnabledChanged(const winrt::IInspectable&, const winrt::DependencyPropertyChangedEventArgs&)
+{
+    UpdateVisualStateForIsEnabledChange();
+}
+
+void NumberBox::UpdateVisualStateForIsEnabledChange()
+{
+    winrt::VisualStateManager::GoToState(*this, IsEnabled() ? L"Normal" : L"Disabled", false);
+}
+
 void NumberBox::OnNumberBoxGotFocus(winrt::IInspectable const& sender, winrt::RoutedEventArgs const& args)
 {
     // When the control receives focus, select the text

dev/NumberBox/NumberBox.h

@@ -68,7 +68,8 @@ class NumberBox :
     void OnNumberBoxGotFocus(winrt::IInspectable const& sender, winrt::RoutedEventArgs const& args);
     void OnNumberBoxLostFocus(winrt::IInspectable const& sender, winrt::RoutedEventArgs const& args);
     void OnNumberBoxScroll(winrt::IInspectable const& sender, winrt::PointerRoutedEventArgs const& args);
-    void OnCornerRadiusPropertyChanged(const winrt::DependencyObject& /*sender*/, const winrt::DependencyProperty& /*args*/);
+    void OnCornerRadiusPropertyChanged(const winrt::DependencyObject&, const winrt::DependencyProperty&);
+    void OnIsEnabledChanged(const winrt::IInspectable&, const winrt::DependencyPropertyChangedEventArgs&);
 
     void ValidateInput();
     void CoerceMinimum();
@@ -83,6 +84,8 @@ class NumberBox :
 
     void UpdateHeaderPresenterState();
 
+    void UpdateVisualStateForIsEnabledChange();
+
     bool IsInBounds(double value);
 
     void MoveCaretToTextEnd();
@@ -105,4 +108,6 @@ class NumberBox :
     winrt::RepeatButton::Click_revoker m_popupDownButtonClickRevoker{};
 
     PropertyChanged_revoker m_cornerRadiusChangedRevoker{};
+
+    winrt::Control::IsEnabledChanged_revoker m_isEnabledChangedRevoker{};
 };

dev/NumberBox/NumberBox.xaml

@@ -20,6 +20,14 @@
                 <ControlTemplate TargetType="local:NumberBox">
                     <Grid>
                         <VisualStateManager.VisualStateGroups>
+                            <VisualStateGroup x:Name="CommonStates">
+                                <VisualState x:Name="Normal" />
+                                <VisualState x:Name="Disabled">
+                                    <VisualState.Setters>
+                                        <Setter Target="HeaderContentPresenter.Foreground" Value="{ThemeResource TextControlHeaderForegroundDisabled}"/>
+                                    </VisualState.Setters>
+                                </VisualState>
+                            </VisualStateGroup>
                             <VisualStateGroup x:Name="SpinButtonStates">
                                 <VisualState x:Name="SpinButtonsCollapsed" />