fix: Handle NullExtension in XAML code generation

unoplatform · Oct 7, 2020 · 25a08ce · 25a08ce
1 parent 3ef3dfd
commit 25a08ce
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Showing 3 changed files with 27 additions and 1 deletion.
diff --git a/src/SourceGenerators/Uno.UI.SourceGenerators/XamlGenerator/XamlFileGenerator.cs b/src/SourceGenerators/Uno.UI.SourceGenerators/XamlGenerator/XamlFileGenerator.cs
@@ -4250,6 +4250,11 @@ private string BuildBindingOption(XamlMemberDefinition m, INamedTypeSymbol prope
 					return $"new RelativeSource(RelativeSourceMode.{resourceName})";
 				}
 
+				if (bindingType.Type.Name == "NullExtension")
+				{
+					return "null";
+				}
+
 				// If type specified in the binding was not found, log and return an error message
 				if (!string.IsNullOrEmpty(bindingType?.Type?.Name ?? string.Empty))
 				{

diff --git a/src/Uno.UI.Tests/App/Xaml/Test_Styles.xaml b/src/Uno.UI.Tests/App/Xaml/Test_Styles.xaml
@@ -122,5 +122,6 @@
 			</Setter.Value>
 		</Setter>
 	</Style>
-
+	<Style x:Key="StylesTestNullBasedOn" TargetType="Button" BasedOn="{x:Null}"/>
+	<Style x:Key="StylesTestBasedOn" TargetType="Button" BasedOn="{StaticResource ButtonStyleWithTemplates1}"/>
 </ResourceDictionary>
diff --git a/src/Uno.UI.Tests/Windows_UI_Xaml/Given_Explicit_Style.cs b/src/Uno.UI.Tests/Windows_UI_Xaml/Given_Explicit_Style.cs
@@ -144,5 +144,25 @@ public void When_Inline_Style()
 			var tb = page.TestTextBlock;
 			Assert.AreEqual(38.0, tb.FontSize);
 		}
+
+		[TestMethod]
+		public void When_Style_BasedOn_Is_Null()
+		{
+			var app = UnitTestsApp.App.EnsureApplication();
+
+			var button1 = new Button { Style = app.Resources["StylesTestNullBasedOn"] as Style };
+
+			app.HostView.Children.Add(button1);
+			button1.Measure(new Size(1000, 1000));
+
+			Assert.IsNull(button1.Style.BasedOn);
+
+			var button2 = new Button { Style = app.Resources["StylesTestBasedOn"] as Style };
+
+			app.HostView.Children.Add(button2);
+			button2.Measure(new Size(1000, 1000));
+
+			Assert.IsNotNull(button2.Style.BasedOn);
+		}
 	}
 }