Add Multiple Contract Resolver in Newtonsoft.Json

Question

Blueprint for data structure:

public class Movie
{
    public string Name { get; set; }
}

Using Newtonsoft.Json, I have the following confi

Answer 1

I find it's a much better idea to create a composite-contract-resolver. This is what I use in my projects:

public class CompositeContractResolver : IContractResolver, IEnumerable
{
    private readonly IList _contractResolvers = new List();

    public JsonContract ResolveContract(Type type)
    {
        return
            _contractResolvers
                .Select(x => x.ResolveContract(type))
                .FirstOrDefault(Conditional.IsNotNull);
    }

    public void Add([NotNull] IContractResolver contractResolver)
    {
        if (contractResolver == null) throw new ArgumentNullException(nameof(contractResolver));
        _contractResolvers.Add(contractResolver);
    }

    public IEnumerator GetEnumerator()
    {
        return _contractResolvers.GetEnumerator();
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        return GetEnumerator();
    }
}

I then use it like this:

Settings = new JsonSerializerSettings
{
    ContractResolver = new CompositeContractResolver
    {
        new InterfaceContractResolver(),
        new DefaultContractResolver()
    }
}

where my custom contract-resolvers return a null contract so the composite one can fall through the default one if there is no match.

public class InterfaceContractResolver : DefaultContractResolver
{
    public InterfaceContractResolver()
    {
        if (!typeof(T).IsInterface) throw new InvalidOperationException("T must be an interface.");
    }

    public override JsonContract ResolveContract(Type type)
    {
        return 
            typeof(T).IsAssignableFrom(type) 
                ? base.ResolveContract(typeof(T)) 
                : default;
    }

    protected override IList CreateProperties(Type type, MemberSerialization memberSerialization)
    {
        return
            typeof(T).IsAssignableFrom(type)
                ? base.CreateProperties(typeof(T), memberSerialization)
                : default;
    }
}