RadialGauge UIA improvements (#3544)

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## Fixes #
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Fixes #3537 , Fixes #3539 , Fixes #3542 (this PR is all we can do, see microsoft/microsoft-ui-xaml#3469)

<!-- Add a brief overview here of the feature/bug & fix. -->

The issues with the sample were caused by microsoft/microsoft-ui-xaml#3467 , switching to RangeBaseAutomationPeer as base class for the RadialGauge peer fixes that.

Afaik, the only thing we can (and should do) for #3542 is raise the appropriate event on the AutomationPeer.

## PR Type
What kind of change does this PR introduce?
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Bugfix
<!-- - Feature -->
<!-- - Code style update (formatting) -->
<!-- - Refactoring (no functional changes, no api changes) -->
<!-- - Build or CI related changes -->
<!-- - Documentation content changes -->
<!-- - Sample app changes -->
<!-- - Other... Please describe: -->


## What is the current behavior?
<!-- Please describe the current behavior that you are modifying, or link to a relevant issue. -->

RadialGauge is not accessible

## What is the new behavior?
<!-- Describe how was this issue resolved or changed? -->

RadialGauge is accessible

## PR Checklist

Please check if your PR fulfills the following requirements:

- [x] Tested code with current [supported SDKs](../readme.md#supported)
- [ ] Pull Request has been submitted to the documentation repository [instructions](..\contributing.md#docs). Link: <!-- docs PR link -->
- [ ] Sample in sample app has been added / updated (for bug fixes / features)
    - [ ] Icon has been created (if new sample) following the [Thumbnail Style Guide and templates](https://github.com/windows-toolkit/WindowsCommunityToolkit-design-assets)
- [x] Tests for the changes have been added (for bug fixes / features) (if applicable)
- [x] Header has been added to all new source files (run *build/UpdateHeaders.bat*)
- [Maybe?] Contains **NO** breaking changes

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     Please note that breaking changes are likely to be rejected within minor release cycles or held until major versions. -->


## Other information

I left out the RangeSelector from this PR as fixing that controls behavior needs more discussion on how to approach that.

Author: msftbot[bot]

Microsoft.Toolkit.Uwp.UI.Controls/RadialGauge/RadialGauge.cs

@@ -469,6 +469,11 @@ protected override void OnValueChanged(double oldValue, double newValue)
         {
             OnValueChanged(this);
             base.OnValueChanged(oldValue, newValue);
+            if (AutomationPeer.ListenerExists(AutomationEvents.LiveRegionChanged))
+            {
+                var peer = FrameworkElementAutomationPeer.FromElement(this) as RadialGaugeAutomationPeer;
+                peer?.RaiseValueChangedEvent(oldValue, newValue);
+            }
         }
 
         private static void OnValueChanged(DependencyObject d)

Microsoft.Toolkit.Uwp.UI.Controls/RadialGauge/RadialGaugeAutomationPeer.cs

@@ -3,6 +3,8 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Collections.Generic;
+using Windows.Foundation;
+using Windows.UI.Xaml.Automation;
 using Windows.UI.Xaml.Automation.Peers;
 using Windows.UI.Xaml.Automation.Provider;
 
@@ -12,7 +14,7 @@ namespace Microsoft.Toolkit.Uwp.UI.Controls
     /// Exposes <see cref="RadialGauge"/> to Microsoft UI Automation.
     /// </summary>
     public class RadialGaugeAutomationPeer :
-        FrameworkElementAutomationPeer,
+        RangeBaseAutomationPeer,
         IRangeValueProvider
     {
         /// <summary>
@@ -25,25 +27,25 @@ public RadialGaugeAutomationPeer(RadialGauge owner)
         }
 
         /// <inheritdoc/>
-        public bool IsReadOnly => !((RadialGauge)Owner).IsInteractive;
+        public new bool IsReadOnly => !((RadialGauge)Owner).IsInteractive;
 
         /// <inheritdoc/>
-        public double LargeChange => ((RadialGauge)Owner).StepSize;
+        public new double LargeChange => ((RadialGauge)Owner).StepSize;
 
         /// <inheritdoc/>
-        public double Maximum => ((RadialGauge)Owner).Maximum;
+        public new double Maximum => ((RadialGauge)Owner).Maximum;
 
         /// <inheritdoc/>
-        public double Minimum => ((RadialGauge)Owner).Minimum;
+        public new double Minimum => ((RadialGauge)Owner).Minimum;
 
         /// <inheritdoc/>
-        public double SmallChange => ((RadialGauge)Owner).StepSize;
+        public new double SmallChange => ((RadialGauge)Owner).StepSize;
 
         /// <inheritdoc/>
-        public double Value => ((RadialGauge)Owner).Value;
+        public new double Value => ((RadialGauge)Owner).Value;
 
         /// <inheritdoc/>
-        public void SetValue(double value)
+        public new void SetValue(double value)
         {
             ((RadialGauge)Owner).Value = value;
         }
@@ -58,7 +60,7 @@ protected override IList<AutomationPeer> GetChildrenCore()
         protected override string GetNameCore()
         {
             var gauge = (RadialGauge)Owner;
-            return "radial gauge. " + (string.IsNullOrWhiteSpace(gauge.Unit) ? "no unit specified. " : "unit " + gauge.Unit + ". ");
+            return "radial gauge. " + (string.IsNullOrWhiteSpace(gauge.Unit) ? "no unit specified, " : "unit " + gauge.Unit + ", ") + Value;
         }
 
         /// <inheritdoc/>
@@ -78,5 +80,15 @@ protected override AutomationControlType GetAutomationControlTypeCore()
         {
             return AutomationControlType.Custom;
         }
+
+        /// <summary>
+        /// Raises the property changed event for this AutomationPeer for the provided identifier.
+        /// </summary>
+        /// <param name="oldValue">Old value</param>
+        /// <param name="newValue">New value</param>
+        public void RaiseValueChangedEvent(double oldValue, double newValue)
+        {
+            RaisePropertyChangedEvent(RangeValuePatternIdentifiers.ValueProperty, PropertyValue.CreateDouble(oldValue), PropertyValue.CreateDouble(newValue));
+        }
     }
 }

UnitTests/UnitTests.UWP/UI/Controls/Test_RadialGauge.cs

@@ -0,0 +1,38 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Microsoft.Toolkit.Uwp.UI.Controls;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Microsoft.VisualStudio.TestTools.UnitTesting.AppContainer;
+using Windows.UI.Xaml.Automation.Peers;
+
+namespace UnitTests.UWP.UI.Controls
+{
+    [TestClass]
+    public class Test_RadialGauge
+    {
+        /// <summary>
+        /// Verifies that the UIA name is valid and makes sense
+        /// </summary>
+        [TestCategory("Test_TextToolbar_Localization")]
+        [UITestMethod]
+        public void VerifyUIAName()
+        {
+            var gauge = new RadialGauge()
+            {
+                Minimum = 0,
+                Maximum = 100,
+                Value = 20
+            };
+
+            var gaugePeer = FrameworkElementAutomationPeer.CreatePeerForElement(gauge);
+
+            Assert.IsTrue(gaugePeer.GetName().Contains(gauge.Value.ToString()), "Verify that the UIA name contains the value of the RadialGauge.");
+            Assert.IsTrue(gaugePeer.GetName().Contains("no unit"), "The UIA name should indicate that unit was not specified.");
+
+            gauge.Unit = "KM/H";
+            Assert.IsTrue(gaugePeer.GetName().Contains(gauge.Unit), "The UIA name should report the unit of the RadialGauge.");
+        }
+    }
+}

UnitTests/UnitTests.UWP/UnitTests.UWP.csproj

@@ -179,6 +179,7 @@
     <Compile Include="PrivateType.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Helpers\Test_WeakEventListener.cs" />
+    <Compile Include="UI\Controls\Test_RadialGauge.cs" />
     <Compile Include="UI\Controls\Test_TextToolbar_Localization.cs" />
     <Compile Include="UI\Controls\Test_InfiniteCanvas_Regression.cs" />
     <Compile Include="UI\Controls\Test_TokenizingTextBox_General.cs" />
@@ -498,4 +499,4 @@
   <Target Name="AfterBuild">
   </Target>
   -->
-</Project>
+</Project>