From 56af2878e6c4f47c197617f7e8735c09d365b535 Mon Sep 17 00:00:00 2001
From: Rob Horvath <robhorvath@gmail.com>
Date: Mon, 3 Dec 2012 15:59:16 -0500
Subject: [PATCH] Fix for Issue #131

BindingTypeConverters EqualityTypeConverter.DoReferenceCast doesn't
handle nullable values
---
 ReactiveUI.Tests/BindingTypeConvertersTest.cs | 23 +++++++++++++++++++
 ReactiveUI.Tests/ReactiveUI.Tests.csproj      |  3 ++-
 ReactiveUI/BindingTypeConverters.cs           | 20 ++++++++--------
 3 files changed, 36 insertions(+), 10 deletions(-)
 create mode 100644 ReactiveUI.Tests/BindingTypeConvertersTest.cs

diff --git a/ReactiveUI.Tests/BindingTypeConvertersTest.cs b/ReactiveUI.Tests/BindingTypeConvertersTest.cs
new file mode 100644
index 0000000000..ada9ab4034
--- /dev/null
+++ b/ReactiveUI.Tests/BindingTypeConvertersTest.cs
@@ -0,0 +1,23 @@
+using Xunit;
+
+namespace ReactiveUI.Tests
+{
+    public class BindingTypeConvertersTest
+    {
+        [Fact]
+        public void EqualityTypeConverterDoReferenceCastShouldConvertNullableValues()
+        {
+            double? nullableDouble = 0.0;
+            var result = EqualityTypeConverter.DoReferenceCast<double?>(nullableDouble);
+            Assert.Equal(nullableDouble, result);
+        }
+
+        [Fact]
+        public void EqualityTypeConverterDoReferenceCastShouldConvertValueTypes()
+        {
+            double doubleValue = 0.0;
+            var result = EqualityTypeConverter.DoReferenceCast<double>(doubleValue);
+            Assert.Equal(doubleValue, result);
+        }
+    }
+}
\ No newline at end of file
diff --git a/ReactiveUI.Tests/ReactiveUI.Tests.csproj b/ReactiveUI.Tests/ReactiveUI.Tests.csproj
index 1c7d6a9809..c2a1f68b2f 100644
--- a/ReactiveUI.Tests/ReactiveUI.Tests.csproj
+++ b/ReactiveUI.Tests/ReactiveUI.Tests.csproj
@@ -93,6 +93,7 @@
     </CodeAnalysisDependentAssemblyPaths>
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="BindingTypeConvertersTest.cs" />
     <Compile Include="CommandBindingTests.cs" />
     <Compile Include="DependencyObjectObservableForPropertyTest.cs" />
     <Compile Include="ErrorsTest.cs" />
@@ -134,4 +135,4 @@
   <Target Name="AfterBuild">
   </Target>
   -->
-</Project>
+</Project>
\ No newline at end of file
diff --git a/ReactiveUI/BindingTypeConverters.cs b/ReactiveUI/BindingTypeConverters.cs
index cfdd623e9e..c86e564bbc 100644
--- a/ReactiveUI/BindingTypeConverters.cs
+++ b/ReactiveUI/BindingTypeConverters.cs
@@ -42,16 +42,18 @@ public bool TryConvert(object from, Type toType, object conversionHint, out obje
 
         public static object DoReferenceCast<T>(object from)
         {
-#if WINRT
-            bool isValueType = typeof (T).GetTypeInfo().IsValueType;
-#else
-            bool isValueType = typeof (T).IsValueType;
-#endif
-            if (isValueType) {
-                return System.Convert.ChangeType(from, typeof (T), null);
-            } else {
-                return (T) from;
+            var t = typeof (T);
+            var u = Nullable.GetUnderlyingType(t);
+
+            if (u == null) {
+                return (T) Convert.ChangeType(from, t);
             }
+
+            if (from == null) {
+                return default(T);
+            }
+
+            return (T) Convert.ChangeType(from, u);
         }
     }