fix: NullReferenceException

src/SamplesApp/UITests.Shared/Microsoft_UI_Xaml_Controls/ProgressRing/WinUIDeterminateProgressRing.xaml.cs

@@ -21,7 +21,10 @@ public WinUIDeterminateProgressRing()
 
 		private void ProgressValue_SelectionChanged(object sender, SelectionChangedEventArgs e)
 		{
-			ProgressRing.Value = double.Parse(ProgressValue.SelectedValue as string);
+			if (ProgressRing is { })
+			{
+				ProgressRing.Value = double.Parse(ProgressValue.SelectedValue as string);
+			}
 		}
 	}
 }

src/SamplesApp/UITests.Shared/Microsoft_UI_Xaml_Controls/TabViewTests/TabViewPage.xaml.cs

@@ -43,7 +43,7 @@ public sealed partial class TabViewPage : Page
 		public TabViewPage()
 		{
 			this.InitializeComponent();
-			Loaded += TabViewPage_Loaded;
+			DisabledTab.Loaded += TabViewPage_Loaded;
 			_iconSource = new SymbolIconSource();
 			_iconSource.Symbol = Symbol.Placeholder;
 

src/SamplesApp/UITests.Shared/Windows_Devices/OrientationTests.xaml

@@ -14,6 +14,6 @@
 			<RowDefinition Height="Auto" />
 		</Grid.RowDefinitions>
 		<TextBlock Grid.Row="0" TextWrapping="Wrap"  x:Name="timeSince" />
-		<TextBlock Grid.Row="1" TextWrapping="Wrap"  Text="This is mainly for mobile. It should not take longer than 1 or 2 seconds for the orientation event to happen once orientation changes."/>
+		<TextBlock Grid.Row="1" TextWrapping="Wrap"  Text="This is mainly for mobile. It should not take longer than 1 or 2 seconds for the orientation event to happen once orientation changes." x:Name="message"/>
 	</Grid>
 </Page>

src/SamplesApp/UITests.Shared/Windows_Devices/OrientationTests.xaml.cs

@@ -12,21 +12,34 @@ public sealed partial class OrientationTests : Page
 	{
 		long lastTime;
 		public OrientationTests()
-        {
-            this.InitializeComponent();
+		{
+			this.InitializeComponent();
 			lastTime = DateTime.UtcNow.ToUnixTimeMilliseconds();
-			SimpleOrientationSensor.GetDefault().OrientationChanged += OnSensorOrientationChanged;
+			this.Loaded += (s, e) =>
+			{
+				var sensor = SimpleOrientationSensor.GetDefault();
+				if (sensor is { })
+				{
+					sensor.OrientationChanged += OnSensorOrientationChanged;
+				}
+				else
+				{
+					message.Text = "This device does not have an orientation sensor.";
+				}
+			};
 		}
 
-        private void OnSensorOrientationChanged(SimpleOrientationSensor sender, SimpleOrientationSensorOrientationChangedEventArgs args)
-        {
-	        var now = DateTime.UtcNow.ToUnixTimeMilliseconds();
 
-	        var diff = now - lastTime;
-	        var s = diff / 1000;
-	        var ms = diff % 1000;
-	        timeSince.Text = $"~{s}.{ms} seconds since last orientation change.";
-	        lastTime = now;
-        }
-    }
+
+		private void OnSensorOrientationChanged(SimpleOrientationSensor sender, SimpleOrientationSensorOrientationChangedEventArgs args)
+		{
+			var now = DateTime.UtcNow.ToUnixTimeMilliseconds();
+
+			var diff = now - lastTime;
+			var s = diff / 1000;
+			var ms = diff % 1000;
+			timeSince.Text = $"~{s}.{ms} seconds since last orientation change.";
+			lastTime = now;
+		}
+	}
 }