Question

I am writing some custom generic data structures. How can I ensure that the generic type passed in can be serialized by protobuf-net? Since protobuf-net doesn’t rely on interfaces, I can’t constrain the type parameter in that way. I thought about runtime testing of the type inside the constructor, but I can’t even use PrepareSerializer<T> because that relies on the type being a reference type. I could simply attempting a serialization and deserialization, but this seems messy at best. What’s the best way to verify the a given generic type can be serialized?

Answer 1

XmlProtoSerializer has to make a similar determination. For example:

static int GetKey(TypeModel model, ref Type type, out bool isList)
{
    if (model != null && type != null)
    {
        int key = model.GetKey(ref type);
        if (key >= 0)
        {
             isList = false;
             return key;
        }
        Type itemType = TypeModel.GetListItemType(type);
        if (itemType != null)
        {
            key = model.GetKey(ref itemType);
            if (key >= 0)
            {
                isList = true;
                return key;
            }
        }
    }

    isList = false;
    return -1;
}

If that returns a negative value it can’t be serialised. I could make this available in a more supported bool CanSerialize(Type) if that would be helpful?