Protobuf-net: Instances of abstract classes cannot be created.

Answer 1

Is there a reason you need to separate ProtoObject and ProtoObject<T>? protobuf-net seems to create an object of type T (in a roundabout way) in ObjectFactory, and I'm assuming that T is going to be ProtoObject, which is abstract.

Sorry I'm not more helpful - I don't have too much time to dig further right at the moment.

Answer 2

This may be simply a limitation in "v1". I've added this as a test on "v2", and it passed (I had to invent UrlStatus and TrafficEntry to get it to compile):

    public enum UrlStatus { A,B }
    public enum TrafficEntry { A }
    [ProtoContract]
    public class SerializableException { }

    [Test]
    public void TestBasicRoundTrip()
    {
        var item = new ProtoDictionary<string>();
        item.Add("abc", "def");
        item.Add("ghi", new List<UrlStatus> {UrlStatus.A, UrlStatus.B});

        var clone = Serializer.DeepClone(item);
        Assert.AreEqual(2, clone.Keys.Count);
        object o = clone["abc"];
        Assert.AreEqual("def", clone["abc"].Value);
        var list = (IList<UrlStatus>)clone["ghi"].Value;
        Assert.AreEqual(2, list.Count);
        Assert.AreEqual(UrlStatus.A, list[0]);
        Assert.AreEqual(UrlStatus.B, list[1]);
    }

With "v1", maybe simply don't make it abstract? (workaround, not fix)

Also; there should be no need for the SerializationInfo ctor; that is not used by protobuf-net (although you can implement protobuf-net inside BinaryFormatter by providing this method and calling into Merge)