How do I find settable properties with Json.NET using a ContractResolver?

Question

I'm trying to just serialize settable properties using Json.NET. I have a custom ContractResolver and am trying to ignore readonly properties using the Writable property of a JsonProperty class.

The test below fails. I would expect that the property is 'Writable = true' because there is only a 'get' definition on the property Bar.

Is there another way of doing this?

As a side note, the reason for serializing this way is that it will save a lot of unnecessary properties serializations. The source and destination object will be the same, so there's not much point in loading up the json with unnecessary properties.

     [TestClass]
            public class JsonDotNet_WriteOnlyTests
            {
                private class FooContractResolver : DefaultContractResolver
                {
                    protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
                    {
                        IList<JsonProperty> properties = base.CreateProperties(type, MemberSerialization.Fields);

                        //ignore all readonly properties
                        var readOnlyProps = properties.Where(w => !w.Writable);
                        foreach (var readonlyProp in readOnlyProps)
                        {
                            readonlyProp.Ignored = true;
                        }

                        return properties;
                    }
                }

                private class Foo
                {
                    public string Name { get; set; }

//I would expect this property to be 'Writable=false'...
                    public string Bar { get { return "Hey there"; } }
                }

                [TestMethod]
                public void TestWriteOnly()
                {
                    var settings = new JsonSerializerSettings
                    {
                        ContractResolver = new FooContractResolver()
                    };

                    var foos = new []{new Foo{}, new Foo{}};

                    var json = JsonConvert.SerializeObject(foos, settings);

                    Assert.IsFalse(json.Contains("Bar"));
                }
            }