Merge pull request #3728 from unoplatform/dev/dr/SkiaLoad

fix: View not removed and Unloaded event not raised

src/SamplesApp/SamplesApp.UnitTests.Shared/Controls/UITests/Presentation/SampleChooserViewModel.cs

@@ -43,7 +43,11 @@ namespace SampleControl.Presentation
 
 	public partial class SampleChooserViewModel
 	{
+#if DEBUG
 		private const int _numberOfRecentSamplesVisible = 10;
+#else
+		private const int _numberOfRecentSamplesVisible = 0;
+#endif
 		private List<SampleChooserCategory> _categories;
 
 		private readonly Uno.Threading.AsyncLock _fileLock = new Uno.Threading.AsyncLock();
@@ -543,7 +547,11 @@ private static Assembly[] GetAllAssembies()
 		private List<SampleChooserCategory> GetSamples()
 		{
 			var categories =
+#if !__WASM__
+				from assembly in GetAllAssembies().AsParallel()
+#else
 				from assembly in GetAllAssembies()
+#endif
 				from type in FindDefinedAssemblies(assembly)
 				let sampleAttribute = FindSampleAttribute(type)
 				where sampleAttribute != null
@@ -553,7 +561,7 @@ group content by category into contentByCategory
 				orderby contentByCategory.Key.ToLower(CultureInfo.CurrentUICulture)
 				select new SampleChooserCategory(contentByCategory);
 
-			return categories.AsParallel().ToList();
+			return categories.ToList();
 
 			SampleChooserContent GetContent(TypeInfo type, SampleAttribute attribute)
 				=> new SampleChooserContent

src/Uno.UI.RuntimeTests/Tests/Windows_UI_Xaml_Controls/Given_FrameworkElement.cs

@@ -380,6 +380,117 @@ public async Task When_Negative_Margin_Zero_Size()
 
 			Assert.AreEqual(0d, Math.Round(SUT.DesiredSize.Height));
 		}
+
+		[TestMethod]
+		[RunsOnUIThread]
+		public async Task When_Add_Element_Then_Load_Raised()
+		{
+			var sut = new Border();
+			var hostPanel = new Grid();
+
+			TestServices.WindowHelper.WindowContent = hostPanel;
+			await TestServices.WindowHelper.WaitForIdle();
+
+			int loadingCount = 0, loadedCount = 0;
+			sut.Loading += (snd, e) => loadingCount++;
+			sut.Loaded += (snd, e) => loadedCount++;
+
+			hostPanel.Children.Add(sut);
+
+			Assert.AreEqual(1, loadingCount, "loading");
+			Assert.AreEqual(1, loadedCount, "loaded");
+		}
+
+		[TestMethod]
+		[RunsOnUIThread]
+		public async Task When_Add_Element_Then_Unload_Raised()
+		{
+			var sut = new Border();
+			var hostPanel = new Grid {Children = {sut}};
+
+			TestServices.WindowHelper.WindowContent = hostPanel;
+			await TestServices.WindowHelper.WaitForIdle();
+
+			var unloadCount = 0;
+			sut.Unloaded += (snd, e) => unloadCount++;
+
+			hostPanel.Children.Remove(sut);
+
+			Assert.AreEqual(1, unloadCount);
+#if NETSTANDARD2_0
+			Assert.IsFalse(hostPanel._children.Contains(sut));
+#endif
+		}
+
+#if NETSTANDARD2_0
+		// Those tests only validate the current behavior which should be reviewed by https://github.com/unoplatform/uno/issues/2895
+		// (cf. notes in the tests)
+
+		[TestMethod]
+		[RunsOnUIThread]
+		public async Task When_Add_Element_While_Parent_Loading_Then_Load_Raised()
+		{
+			var sut = new Border();
+			var hostPanel = new Grid();
+
+			int loadingCount = 0, loadedCount = 0;
+			var success = false;
+			sut.Loading += (snd, e) => loadingCount++;
+			sut.Loaded += (snd, e) => loadedCount++;
+
+			hostPanel.Loading += (snd, e) =>
+			{
+				hostPanel.Children.Add(sut);
+
+				// Note: This is NOT the case on UWP. Loading and Loaded event are raised on the child (aka. 'sut'')
+				//		 only after the completion of the current handler.
+				Assert.AreEqual(1, loadingCount, "loading");
+				Assert.AreEqual(0, loadedCount, "loaded");
+				success = true;
+			};
+
+			TestServices.WindowHelper.WindowContent = hostPanel;
+			await TestServices.WindowHelper.WaitForIdle();
+
+			Assert.IsTrue(success);
+			Assert.AreEqual(1, loadingCount, "loading");
+			Assert.AreEqual(1, loadedCount, "loaded");
+		}
+
+		[TestMethod]
+		[RunsOnUIThread]
+		public async Task When_Add_Element_While_Parent_Loaded_Then_Load_Raised()
+		{
+			var sut = new Border();
+			var hostPanel = new Grid();
+
+			int loadingCount = 0, loadedCount = 0;
+			var success = false;
+			sut.Loading += (snd, e) => loadingCount++;
+			sut.Loaded += (snd, e) => loadedCount++;
+
+			hostPanel.Loaded += (snd, e) =>
+			{
+				hostPanel.Children.Add(sut);
+
+				// Note: This is NOT the case on UWP. Loading and Loaded event are raised on the child (aka. 'sut'')
+				//		 only after the completion of the current handler.
+				// Note 2: On UWP, when adding a child to the parent while in the parent's loading event handler (i.e. this case)
+				//		   the child will receive the Loaded ** BEFORE ** the Loading event.
+				Assert.AreEqual(1, loadingCount, "loading");
+				Assert.AreEqual(1, loadedCount, "loaded");
+
+				success = true;
+			};
+
+			TestServices.WindowHelper.WindowContent = hostPanel;
+			await TestServices.WindowHelper.WaitForIdle();
+
+			Assert.IsTrue(success);
+			Assert.AreEqual(1, loadingCount, "loading");
+			Assert.AreEqual(1, loadedCount, "loaded");
+		}
+#endif
 	}
 
 	public partial class MyControl01 : FrameworkElement

src/Uno.UI/UI/Xaml/Controls/Panel/Panel.cs

@@ -80,7 +80,7 @@ private void UpdateTransitions(IFrameworkElement element)
 
 		public UIElementCollection Children => _children;
 
-#region ChildrenTransitions Dependency Property
+		#region ChildrenTransitions Dependency Property
 
 		public TransitionCollection ChildrenTransitions
 		{
@@ -143,7 +143,7 @@ public Thickness Padding
 
 #endregion
 
-#region BorderThickness DependencyProperty
+		#region BorderThickness DependencyProperty
 
 		public Thickness BorderThickness
 		{
@@ -163,9 +163,9 @@ public Thickness BorderThickness
 				)
 			);
 
-#endregion
+		#endregion
 
-#region BorderBrush Dependency Property
+		#region BorderBrush Dependency Property
 
 #if XAMARIN_ANDROID
 		private Brush _borderBrushStrongReference;
@@ -195,9 +195,9 @@ public Brush BorderBrush
 					propertyChangedCallback: (s, e) => ((Panel)s).OnBorderBrushChanged((Brush)e.OldValue, (Brush)e.NewValue)
 				)
 			);
-#endregion
+		#endregion
 
-#region CornerRadius DependencyProperty
+		#region CornerRadius DependencyProperty
 
 		public CornerRadius CornerRadius
 		{
@@ -217,9 +217,9 @@ public CornerRadius CornerRadius
 				)
 			);
 
-#endregion
+		#endregion
 
-#region IsItemsHost DependencyProperty
+		#region IsItemsHost DependencyProperty
 		public static DependencyProperty IsItemsHostProperty { get ; } = DependencyProperty.Register(
 			"IsItemsHost", typeof(bool), typeof(Panel), new FrameworkPropertyMetadata(default(bool)));