pythonnet · filmor · May 10, 2017 · May 8, 2017
diff --git a/src/runtime/converter.cs b/src/runtime/converter.cs
@@ -318,6 +318,17 @@ internal static bool ToManagedValue(IntPtr value, Type obType,
                return true;
            }

+            if (obType.IsGenericType && obType.GetGenericTypeDefinition() == typeof(Nullable<>))
+            {
+                if( value == Runtime.PyNone )
+                {
+                    result = null;
+                    return true;
+                }
+                // Set type to underlying type
+                obType = obType.GetGenericArguments()[0];
+            }
+
            if (obType.IsArray)
            {
                return ToArray(value, obType, out result, setError);

diff --git a/src/testing/conversiontest.cs b/src/testing/conversiontest.cs
@@ -32,8 +32,14 @@ public ConversionTest()

        public byte[] ByteArrayField;
        public sbyte[] SByteArrayField;
+
+        public T? Echo<T>(T? arg) where T: struct {
+            return arg;
+        }
+
    }

+

    public interface ISpam
    {

diff --git a/src/tests/test_conversion.py b/src/tests/test_conversion.py
@@ -641,6 +641,8 @@ def test_enum_conversion():

 def test_null_conversion():
    """Test null conversion."""
+    import System
+
    ob = ConversionTest()

    ob.StringField = None
@@ -652,6 +654,10 @@ def test_null_conversion():
    ob.SpamField = None
    assert ob.SpamField is None

+    pi = 22/7
+    assert ob.Echo[System.Double](pi) == pi
+    assert ob.Echo[System.DateTime](None) is None
+
    # Primitive types and enums should not be set to null.

    with pytest.raises(TypeError):