Anyway to get JsonConvert.SerializeObject to ignore the JsonConverter attribute on a property?

Question

I have a class that I cannot change:

public enum MyEnum {
    Item1 = 0,
    Item2 = 1
}
public class foo {
    [JsonConverter(typeof(StringEnumConverter))]
         


        

Answer 1

This is possible, but the process is a tad involved.

The basic idea is to create a custom ContractResolver and override its CreateProperty method. Something like so:

internal sealed class MyContractResolver : DefaultContractResolver
{
    protected override JsonProperty CreateProperty( MemberInfo member, MemberSerialization memberSerialization )
    {
        var property = base.CreateProperty( member, memberSerialization );

        if( member.DeclaringType == typeof( foo ) && property.PropertyType == typeof( MyEnum ) )
        {
            property.Converter = null;
        }

        return property;
    }
}

You'll also need to actually instantiate this class and pass it into your serializer/deserializer. What that looks like depends on exactly how you're doing the serialization, so I can't guarantee a relevant example of how to use it.

If you're just using the static SerializeObject method:

JsonConvert.SerializeObject( valueToSerialize, new SerializerSettings { ContractResolver = new MyContractResolver() } );

Answer 2

I do not believe you can, as it is part of the definition. You'll have to remove the attribute and add the converter to the serializer settings instead:

var serializerSettings = new JsonSerializerSettings
{
    NullValueHandling = NullValueHandling.Ignore,
    DefaultValueHandling = DefaultValueHandling.IgnoreAndPopulate,

    Converters = new List<JsonConverter> { new StringEnumConverter() },

    ContractResolver = new Newtonsoft.Json.Serialization.CamelCasePropertyNamesContractResolver()
};

In that case you can omit it if you don't want to use it. There is one thing I forgot to mention, the converter has to check the type in CanConvert:

public class StringEnumConverter: JsonConverter
{
    public override bool CanConvert(Type objectType)
    {
        return typeof(MyEnum);
    }
}

I didn't test the code, but you'll get the idea.