[Xaml] Add provided value to collection (#4456)

Xamarin.Forms.Xaml.UnitTests/ApplyPropertiesVisitorTests.cs

@@ -0,0 +1,47 @@
+using NUnit.Framework;
+using System.Collections;
+using Xamarin.Forms.Xaml;
+
+namespace Xamarin.Forms.Xaml.UnitTests
+{
+	[TestFixture]
+	public static class ApplyPropertiesVisitorTests
+	{
+		public class MarkupExtension : IMarkupExtension
+		{
+			public object ProvideValue(System.IServiceProvider serviceProvider)
+			{
+				return "provided value";
+			}
+		}
+
+		public class ArrayListOwner
+		{
+			public ArrayList ArrayList { get; } = new ArrayList();
+		}
+
+		[Test]
+		public static void ProvideValueForCollectionItem()
+		{
+			const string NAMESPACE = "clr-namespace:Xamarin.Forms.Xaml.UnitTests;assembly=Xamarin.Forms.Xaml.UnitTests";
+			var resolver = new MockNameSpaceResolver();
+			var type = new XmlType(NAMESPACE, "ApplyPropertiesVisitorTests+MarkupExtension", null);
+			var listNode = new ListNode(new[]
+			{
+				new ElementNode(type, NAMESPACE, resolver),
+				new ElementNode(type, NAMESPACE, resolver)
+			}, resolver);
+			var rootElement = new ArrayListOwner();
+			var rootType = new XmlType(NAMESPACE, "ApplyPropertiesVisitorTests+ArrayListOwner", null);
+			var rootNode = new XamlLoader.RuntimeRootNode(rootType, rootElement, null);
+			var context = new HydrationContext { RootElement = rootElement };
+
+			rootNode.Properties.Add(new XmlName(null, "ArrayList"), listNode);
+			rootNode.Accept(new XamlNodeVisitor((node, parent) => node.Parent = parent), null);
+			rootNode.Accept(new CreateValuesVisitor(context), null);
+			rootNode.Accept(new ApplyPropertiesVisitor(context), null);
+
+			CollectionAssert.AreEqual(new[] { "provided value", "provided value" }, rootElement.ArrayList);
+		}
+	}
+}

Xamarin.Forms.Xaml/ApplyPropertiesVisitor.cs

@@ -161,7 +161,7 @@ namespace Xamarin.Forms.Xaml
 
 				MethodInfo addMethod;
 				if (xpe == null && (addMethod = collection.GetType().GetRuntimeMethods().First(mi => mi.Name == "Add" && mi.GetParameters().Length == 1)) != null) {
-					addMethod.Invoke(collection, new[] { Values[node] });
+					addMethod.Invoke(collection, new[] { value });
 					return;
 				}
 				xpe = xpe ?? new XamlParseException($"Value of {parentList.XmlName.LocalName} does not have a Add() method", node);