Xaml convert on add (#273)

* [Xaml] add test for conversion on Set and Add

* [Xaml] Fix conversion on Add()

* [XamlC] use op_implicit before Add()

10 files changed, 113 insertions, 75 deletions

diff --git a/Xamarin.Forms.Build.Tasks/SetPropertiesVisitor.cs b/Xamarin.Forms.Build.Tasks/SetPropertiesVisitor.cs
index 16eddb41..a1c0711a 100644
--- a/Xamarin.Forms.Build.Tasks/SetPropertiesVisitor.cs
+++ b/Xamarin.Forms.Build.Tasks/SetPropertiesVisitor.cs
@@ -141,10 +141,10 @@ namespace Xamarin.Forms.Build.Tasks
 			}
 			else if (IsCollectionItem(node, parentNode) && parentNode is ListNode)
 			{
-				//				IL_000d:  ldloc.2 
-				//				IL_000e:  callvirt instance class [mscorlib]System.Collections.Generic.IList`1<!0> class [Xamarin.Forms.Core]Xamarin.Forms.Layout`1<class [Xamarin.Forms.Core]Xamarin.Forms.View>::get_Children()
-				//				IL_0013:  ldloc.0 
-				//				IL_0014:  callvirt instance void class [mscorlib]System.Collections.Generic.ICollection`1<class [Xamarin.Forms.Core]Xamarin.Forms.View>::Add(!0)
+//				IL_000d:  ldloc.2 
+//				IL_000e:  callvirt instance class [mscorlib]System.Collections.Generic.IList`1<!0> class [Xamarin.Forms.Core]Xamarin.Forms.Layout`1<class [Xamarin.Forms.Core]Xamarin.Forms.View>::get_Children()
+//				IL_0013:  ldloc.0 
+//				IL_0014:  callvirt instance void class [mscorlib]System.Collections.Generic.ICollection`1<class [Xamarin.Forms.Core]Xamarin.Forms.View>::Add(!0)
 
 				var parentList = (ListNode)parentNode;
 				var parent = Context.Variables[((IElementNode)parentNode.Parent)];
@@ -314,16 +314,16 @@ namespace Xamarin.Forms.Build.Tasks
 			GetNameAndTypeRef(ref elementType, propertyName.NamespaceURI, ref localName, context, iXmlLineInfo);
 
 			//If the target is an event, connect
-			//			IL_0007:  ldloc.0 
-			//			IL_0008:  ldarg.0 
-			//
-			//			IL_0009:  ldftn instance void class Xamarin.Forms.Xaml.XamlcTests.MyPage::OnButtonClicked(object, class [mscorlib]System.EventArgs)
+//			IL_0007:  ldloc.0 
+//			IL_0008:  ldarg.0 
+//
+//			IL_0009:  ldftn instance void class Xamarin.Forms.Xaml.XamlcTests.MyPage::OnButtonClicked(object, class [mscorlib]System.EventArgs)
 			//OR, if the handler is virtual
-			//			    IL_000x:  ldarg.0 
-			//			    IL_0009:  ldvirtftn instance void class Xamarin.Forms.Xaml.XamlcTests.MyPage::OnButtonClicked(object, class [mscorlib]System.EventArgs)
-			//
-			//			IL_000f:  newobj instance void class [mscorlib]System.EventHandler::'.ctor'(object, native int)
-			//			IL_0014:  callvirt instance void class [Xamarin.Forms.Core]Xamarin.Forms.Button::add_Clicked(class [mscorlib]System.EventHandler)
+//			IL_000x:  ldarg.0 
+//			IL_0009:  ldvirtftn instance void class Xamarin.Forms.Xaml.XamlcTests.MyPage::OnButtonClicked(object, class [mscorlib]System.EventArgs)
+//
+//			IL_000f:  newobj instance void class [mscorlib]System.EventHandler::'.ctor'(object, native int)
+//			IL_0014:  callvirt instance void class [Xamarin.Forms.Core]Xamarin.Forms.Button::add_Clicked(class [mscorlib]System.EventHandler)
 
 			var eventinfo = elementType.GetEvent(ed => ed.Name == localName);
 			if (eventinfo != null)
@@ -409,10 +409,10 @@ namespace Xamarin.Forms.Build.Tasks
 			}
 
 			//If it's a BP, SetValue ()
-			//			IL_0007:  ldloc.0 
-			//			IL_0008:  ldsfld class [Xamarin.Forms.Core]Xamarin.Forms.BindableProperty [Xamarin.Forms.Core]Xamarin.Forms.Label::TextProperty
-			//			IL_000d:  ldstr "foo"
-			//			IL_0012:  callvirt instance void class [Xamarin.Forms.Core]Xamarin.Forms.BindableObject::SetValue(class [Xamarin.Forms.Core]Xamarin.Forms.BindableProperty, object)
+//			IL_0007:  ldloc.0 
+//			IL_0008:  ldsfld class [Xamarin.Forms.Core]Xamarin.Forms.BindableProperty [Xamarin.Forms.Core]Xamarin.Forms.Label::TextProperty
+//			IL_000d:  ldstr "foo"
+//			IL_0012:  callvirt instance void class [Xamarin.Forms.Core]Xamarin.Forms.BindableObject::SetValue(class [Xamarin.Forms.Core]Xamarin.Forms.BindableProperty, object)
 			if (bpRef != null)
 			{
 				//TODO: check if parent is a BP
@@ -454,9 +454,9 @@ namespace Xamarin.Forms.Build.Tasks
 			}
 
 			//If it's a property, set it
-			//			IL_0007:  ldloc.0 
-			//			IL_0008:  ldstr "foo"
-			//			IL_000d:  callvirt instance void class [Xamarin.Forms.Core]Xamarin.Forms.Label::set_Text(string)
+//			IL_0007:  ldloc.0 
+//			IL_0008:  ldstr "foo"
+//			IL_000d:  callvirt instance void class [Xamarin.Forms.Core]Xamarin.Forms.Label::set_Text(string)
 			PropertyDefinition property = elementType.GetProperty(pd => pd.Name == localName, out declaringTypeReference);
 			MethodDefinition propertySetter;
 			if (property != null && (propertySetter = property.SetMethod) != null && propertySetter.IsPublic)
@@ -483,28 +483,7 @@ namespace Xamarin.Forms.Build.Tasks
 				if (valueNode is IElementNode)
 				{
 					var vardef = context.Variables[(ElementNode)valueNode];
-					var implicitOperators =
-						vardef.VariableType.GetMethods(md => md.IsPublic && md.IsStatic && md.IsSpecialName && md.Name == "op_Implicit",
-							module).ToList();
-					MethodReference implicitOperator = null;
-					if (implicitOperators.Any())
-					{
-						foreach (var op in implicitOperators)
-						{
-							var cast = op.Item1;
-							var opDeclTypeRef = op.Item2;
-							var castDef = module.Import(cast).ResolveGenericParameters(opDeclTypeRef, module);
-							var returnType = castDef.ReturnType;
-							if (returnType.IsGenericParameter)
-								returnType = ((GenericInstanceType)opDeclTypeRef).GenericArguments[((GenericParameter)returnType).Position];
-							if (returnType.FullName == propertyType.FullName &&
-							    cast.Parameters[0].ParameterType.Name == vardef.VariableType.Name)
-							{
-								implicitOperator = castDef;
-								break;
-							}
-						}
-					}
+					var implicitOperator = vardef.VariableType.GetImplicitOperatorTo(propertyType, module);
 
 					//TODO replace latest check by a runtime type check
 					if (implicitOperator != null || vardef.VariableType.InheritsFromOrImplements(propertyType) ||
@@ -514,7 +493,7 @@ namespace Xamarin.Forms.Build.Tasks
 						context.IL.Emit(OpCodes.Ldloc, vardef);
 						if (implicitOperator != null)
 						{
-							//						IL_000f:  call !0 class [Xamarin.Forms.Core]Xamarin.Forms.OnPlatform`1<bool>::op_Implicit(class [Xamarin.Forms.Core]Xamarin.Forms.OnPlatform`1<!0>)
+//							IL_000f:  call !0 class [Xamarin.Forms.Core]Xamarin.Forms.OnPlatform`1<bool>::op_Implicit(class [Xamarin.Forms.Core]Xamarin.Forms.OnPlatform`1<!0>)
 							context.IL.Emit(OpCodes.Call, module.Import(implicitOperator));
 						}
 						else if (!vardef.VariableType.IsValueType && propertyType.IsValueType)
@@ -537,6 +516,7 @@ namespace Xamarin.Forms.Build.Tasks
 				var propertyGetterRef = module.Import(propertyGetter);
 				propertyGetterRef = module.Import(propertyGetterRef.ResolveGenericParameters(declaringTypeReference, module));
 				var propertyType = propertyGetterRef.ReturnType.ResolveGenericParameters(declaringTypeReference);
+				var vardef = context.Variables [(ElementNode)valueNode];
 
 				//TODO check md.Parameters[0] type
 				var adderTuple =
@@ -545,12 +525,16 @@ namespace Xamarin.Forms.Build.Tasks
 				{
 					var adderRef = module.Import(adderTuple.Item1);
 					adderRef = module.Import(adderRef.ResolveGenericParameters(adderTuple.Item2, module));
+					var childType = GetParameterType(adderRef.Parameters [0]);
+					var implicitOperator = vardef.VariableType.GetImplicitOperatorTo(childType, module);
 
 					if (valueNode is IElementNode)
 					{
 						context.IL.Emit(OpCodes.Ldloc, parent);
 						context.IL.Emit(OpCodes.Callvirt, propertyGetterRef);
-						context.IL.Emit(OpCodes.Ldloc, context.Variables[(ElementNode)valueNode]);
+						context.IL.Emit(OpCodes.Ldloc, vardef);
+						if (implicitOperator != null)
+							context.IL.Emit(OpCodes.Call, module.Import(implicitOperator));
 						context.IL.Emit(OpCodes.Callvirt, adderRef);
 						if (adderRef.ReturnType.FullName != "System.Void")
 							context.IL.Emit(OpCodes.Pop);
@@ -567,6 +551,14 @@ namespace Xamarin.Forms.Build.Tasks
 			context.IL.Append(br);
 		}
 
+		public static TypeReference GetParameterType(ParameterDefinition param)
+		{
+			if (!param.ParameterType.IsGenericParameter)
+				return param.ParameterType;
+			var type = (param.Method as MethodReference).DeclaringType as GenericInstanceType;
+			return type.GenericArguments [0];
+		}
+
 		static bool GetNameAndTypeRef(ref TypeReference elementType, string namespaceURI, ref string localname,
 			ILContext context, IXmlLineInfo lineInfo)
 		{
diff --git a/Xamarin.Forms.Build.Tasks/TypeReferenceExtensions.cs b/Xamarin.Forms.Build.Tasks/TypeReferenceExtensions.cs
index 89a31765..60e52c80 100644
--- a/Xamarin.Forms.Build.Tasks/TypeReferenceExtensions.cs
+++ b/Xamarin.Forms.Build.Tasks/TypeReferenceExtensions.cs
@@ -200,6 +200,27 @@ namespace Xamarin.Forms.Build.Tasks
 				yield return tuple;
 		}
 
+		public static MethodReference GetImplicitOperatorTo(this TypeReference fromType, TypeReference toType, ModuleDefinition module)
+		{ 
+			var implicitOperators = fromType.GetMethods(md => md.IsPublic && md.IsStatic && md.IsSpecialName && md.Name == "op_Implicit",
+												module).ToList();
+			if (implicitOperators.Any()) {
+				foreach (var op in implicitOperators) {
+					var cast = op.Item1;
+					var opDeclTypeRef = op.Item2;
+					var castDef = module.Import(cast).ResolveGenericParameters(opDeclTypeRef, module);
+					var returnType = castDef.ReturnType;
+					if (returnType.IsGenericParameter)
+						returnType = ((GenericInstanceType)opDeclTypeRef).GenericArguments [((GenericParameter)returnType).Position];
+					if (returnType.FullName == toType.FullName &&
+					    cast.Parameters [0].ParameterType.Name == fromType.Name) {
+						return castDef;
+					}
+				}
+			}
+			return null;
+		}
+
 		public static TypeReference ResolveGenericParameters(this TypeReference self, TypeReference declaringTypeReference)
 		{
 			var genericself = self as GenericInstanceType;
diff --git a/Xamarin.Forms.Xaml.UnitTests/ImplicitConversions.xaml b/Xamarin.Forms.Xaml.UnitTests/BuiltInConversions.xaml
index 38d20e3e..cb0aefb6 100644
--- a/Xamarin.Forms.Xaml.UnitTests/ImplicitConversions.xaml
+++ b/Xamarin.Forms.Xaml.UnitTests/BuiltInConversions.xaml
@@ -2,7 +2,7 @@
 <ContentPage
 		xmlns="http://xamarin.com/schemas/2014/forms"
 		xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
-		x:Class="Xamarin.Forms.Xaml.UnitTests.ImplicitConversions">
+		x:Class="Xamarin.Forms.Xaml.UnitTests.BuiltInConversions">
 	<StackLayout>
 		<DatePicker x:Name="datetime0" Date="2015-01-16"/>
 		<DatePicker x:Name="datetime1">
diff --git a/Xamarin.Forms.Xaml.UnitTests/ImplicitConversions.xaml.cs b/Xamarin.Forms.Xaml.UnitTests/BuiltInConversions.xaml.cs
index 5eae0299..20d4afd2 100644
--- a/Xamarin.Forms.Xaml.UnitTests/ImplicitConversions.xaml.cs
+++ b/Xamarin.Forms.Xaml.UnitTests/BuiltInConversions.xaml.cs
@@ -1,15 +1,12 @@
 using System;
-using System.Collections.Generic;
-
-using Xamarin.Forms;
 
 using NUnit.Framework;
 
 namespace Xamarin.Forms.Xaml.UnitTests
 {
-	public partial class ImplicitConversions : ContentPage
+	public partial class BuiltInConversions : ContentPage
 	{
-		public ImplicitConversions ()
+		public BuiltInConversions ()
 		{
 			InitializeComponent ();
 		}
@@ -20,7 +17,7 @@ namespace Xamarin.Forms.Xaml.UnitTests
 			[Test]
 			public void Datetime ()
 			{
-				var layout = new ImplicitConversions ();
+				var layout = new BuiltInConversions ();
 
 				Assert.AreEqual (new DateTime (2015, 01, 16), layout.datetime0.Date);
 				Assert.AreEqual (new DateTime (2015, 01, 16), layout.datetime1.Date);
@@ -29,7 +26,7 @@ namespace Xamarin.Forms.Xaml.UnitTests
 			[Test]
 			public void String ()
 			{
-				var layout = new ImplicitConversions ();
+				var layout = new BuiltInConversions ();
 
 				Assert.AreEqual ("foobar", layout.label0.Text);
 				Assert.AreEqual ("foobar", layout.label1.Text);
diff --git a/Xamarin.Forms.Xaml.UnitTests/Compiled/FindByName.xaml b/Xamarin.Forms.Xaml.UnitTests/FindByName.xaml
index c0b7afd7..f064e5b0 100644
--- a/Xamarin.Forms.Xaml.UnitTests/Compiled/FindByName.xaml
+++ b/Xamarin.Forms.Xaml.UnitTests/FindByName.xaml
@@ -2,7 +2,7 @@
 <ContentPage 
 	xmlns="http://xamarin.com/schemas/2014/forms" 
 	xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" 
-	x:Class="Xamarin.Forms.Xaml.UnitTests.Compiled.FindByName"
+	x:Class="Xamarin.Forms.Xaml.UnitTests.FindByName"
 	x:Name="root">
 	<StackLayout>
 		<Label Text="Foo" x:Name="label0"/>
diff --git a/Xamarin.Forms.Xaml.UnitTests/Compiled/FindByName.xaml.cs b/Xamarin.Forms.Xaml.UnitTests/FindByName.xaml.cs
index 0ec198e8..c80ca6a6 100644
--- a/Xamarin.Forms.Xaml.UnitTests/Compiled/FindByName.xaml.cs
+++ b/Xamarin.Forms.Xaml.UnitTests/FindByName.xaml.cs
@@ -2,7 +2,7 @@
 
 using Xamarin.Forms;
 
-namespace Xamarin.Forms.Xaml.UnitTests.Compiled
+namespace Xamarin.Forms.Xaml.UnitTests
 {
 	public partial class FindByName : ContentPage
 	{	
diff --git a/Xamarin.Forms.Xaml.UnitTests/Compiled/SetValue.xaml b/Xamarin.Forms.Xaml.UnitTests/SetValue.xaml
index e60cd6db..133e0e9b 100644
--- a/Xamarin.Forms.Xaml.UnitTests/Compiled/SetValue.xaml
+++ b/Xamarin.Forms.Xaml.UnitTests/SetValue.xaml
@@ -2,7 +2,8 @@
 <ContentPage 
 	xmlns="http://xamarin.com/schemas/2014/forms"
 	xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
-	x:Class="Xamarin.Forms.Xaml.UnitTests.Compiled.SetValue">
+	xmlns:local="clr-namespace:Xamarin.Forms.Xaml.UnitTests"
+	x:Class="Xamarin.Forms.Xaml.UnitTests.SetValue">
 	<ContentPage.Resources>
 		<ResourceDictionary>
 			<Color x:Key="purple">Purple</Color>
@@ -67,5 +68,11 @@
 			</Grid.ColumnDefinitions>
 		</Grid>
 		<Label x:Name="label14" AbsoluteLayout.LayoutFlags="PositionProportional,WidthProportional" />
+		<ContentView x:Name="content0">
+			<local:ConvertibleToView/>
+		</ContentView>
+		<StackLayout x:Name="stack4">
+			<local:ConvertibleToView/>
+		</StackLayout>
 	</StackLayout>
 </ContentPage>
\ No newline at end of file
diff --git a/Xamarin.Forms.Xaml.UnitTests/Compiled/SetValue.xaml.cs b/Xamarin.Forms.Xaml.UnitTests/SetValue.xaml.cs
index f835d59f..ce377a71 100644
--- a/Xamarin.Forms.Xaml.UnitTests/Compiled/SetValue.xaml.cs
+++ b/Xamarin.Forms.Xaml.UnitTests/SetValue.xaml.cs
@@ -1,13 +1,18 @@
 using System;
 using System.Linq;
-using System.Collections.Generic;
-
-using Xamarin.Forms;
 
 using NUnit.Framework;
 
-namespace Xamarin.Forms.Xaml.UnitTests.Compiled
+namespace Xamarin.Forms.Xaml.UnitTests
 {
+	public class ConvertibleToView
+	{
+		public static implicit operator View(ConvertibleToView source)
+		{
+			return new Button();
+		}
+	}
+
 	public partial class SetValue : ContentPage
 	{	
 		public SetValue ()
@@ -186,6 +191,22 @@ namespace Xamarin.Forms.Xaml.UnitTests.Compiled
 				var page = new SetValue (useCompiledXaml);
 				Assert.AreEqual (AbsoluteLayoutFlags.PositionProportional | AbsoluteLayoutFlags.WidthProportional, AbsoluteLayout.GetLayoutFlags (page.label14));
 			}
+
+			[TestCase(false)]
+			[TestCase(true)]
+			public void ConversionsAreAppliedOnSet(bool useCompiledXaml)
+			{
+				var page = new SetValue(useCompiledXaml);
+				Assert.That(page.content0.Content, Is.TypeOf<Button>());
+			}
+
+			[TestCase(false)]
+			[TestCase(true)]
+			public void ConversionsAreAppliedOnAdd(bool useCompiledXaml)
+			{
+				var page = new SetValue(useCompiledXaml);
+				Assert.That(page.stack4.Children[0], Is.TypeOf<Button>());
+			}
 		}
 	}
 }
\ No newline at end of file
diff --git a/Xamarin.Forms.Xaml.UnitTests/Xamarin.Forms.Xaml.UnitTests.csproj b/Xamarin.Forms.Xaml.UnitTests/Xamarin.Forms.Xaml.UnitTests.csproj
index cf473ff8..577b68bb 100644
--- a/Xamarin.Forms.Xaml.UnitTests/Xamarin.Forms.Xaml.UnitTests.csproj
+++ b/Xamarin.Forms.Xaml.UnitTests/Xamarin.Forms.Xaml.UnitTests.csproj
@@ -121,9 +121,6 @@
     <Compile Include="Issues\Issue2016.xaml.cs">
       <DependentUpon>Issue2016.xaml</DependentUpon>
     </Compile>
-    <Compile Include="Compiled\FindByName.xaml.cs">
-      <DependentUpon>FindByName.xaml</DependentUpon>
-    </Compile>
     <Compile Include="Validation\SetterOnNonBP.xaml.cs">
       <DependentUpon>SetterOnNonBP.xaml</DependentUpon>
     </Compile>
@@ -143,8 +140,8 @@
     <Compile Include="Issues\Issue2152.xaml.cs">
       <DependentUpon>Issue2152.xaml</DependentUpon>
     </Compile>
-    <Compile Include="ImplicitConversions.xaml.cs">
-      <DependentUpon>ImplicitConversions.xaml</DependentUpon>
+    <Compile Include="BuiltInConversions.xaml.cs">
+      <DependentUpon>BuiltInConversions.xaml</DependentUpon>
     </Compile>
     <Compile Include="Issues\Issue2450.xaml.cs">
       <DependentUpon>Issue2450.xaml</DependentUpon>
@@ -170,9 +167,6 @@
     <Compile Include="Issues\Issue2742.xaml.cs">
       <DependentUpon>Issue2742.xaml</DependentUpon>
     </Compile>
-    <Compile Include="Compiled\SetValue.xaml.cs">
-      <DependentUpon>SetValue.xaml</DependentUpon>
-    </Compile>
     <Compile Include="X2009Primitives.xaml.cs">
       <DependentUpon>X2009Primitives.xaml</DependentUpon>
     </Compile>
@@ -353,6 +347,12 @@
     <Compile Include="Issues\Unreported004.xaml.cs">
       <DependentUpon>Unreported004.xaml</DependentUpon>
     </Compile>
+    <Compile Include="FindByName.xaml.cs">
+      <DependentUpon>FindByName.xaml</DependentUpon>
+    </Compile>
+    <Compile Include="SetValue.xaml.cs">
+      <DependentUpon>SetValue.xaml</DependentUpon>
+    </Compile>
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <Import Project="..\.nuspec\Xamarin.Forms.Debug.targets" />
@@ -422,7 +422,7 @@
     <EmbeddedResource Include="Issues\Issue2152.xaml">
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>
-    <EmbeddedResource Include="ImplicitConversions.xaml">
+    <EmbeddedResource Include="BuiltInConversions.xaml">
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>
     <EmbeddedResource Include="Issues\Issue2450.xaml">
@@ -449,12 +449,6 @@
     <EmbeddedResource Include="Issues\Issue2742.xaml">
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>
-    <EmbeddedResource Include="Compiled\FindByName.xaml">
-      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
-    </EmbeddedResource>
-    <EmbeddedResource Include="Compiled\SetValue.xaml">
-      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
-    </EmbeddedResource>
     <EmbeddedResource Include="X2009Primitives.xaml">
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>
@@ -629,6 +623,12 @@
     <EmbeddedResource Include="Issues\Unreported004.xaml">
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>
+    <EmbeddedResource Include="FindByName.xaml">
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
+    <EmbeddedResource Include="SetValue.xaml">
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
   </ItemGroup>
   <ItemGroup>
     <Service Include="{82A7F48D-3B50-4B1E-B82E-3ADA8210C358}" />
diff --git a/Xamarin.Forms.Xaml/ApplyPropertiesVisitor.cs b/Xamarin.Forms.Xaml/ApplyPropertiesVisitor.cs
index 0a0651a7..6d8792c4 100644
--- a/Xamarin.Forms.Xaml/ApplyPropertiesVisitor.cs
+++ b/Xamarin.Forms.Xaml/ApplyPropertiesVisitor.cs
@@ -417,7 +417,7 @@ namespace Xamarin.Forms.Xaml
 				    null)
 				{
 					addMethod.Invoke(collection,
-						new[] { value.ConvertTo(propertyInfo.PropertyType, (Func<TypeConverter>)null, serviceProvider) });
+					                 new[] { value.ConvertTo(addMethod.GetParameters()[0].ParameterType, (Func<TypeConverter>)null, serviceProvider) });
 					return;
 				}
 			}