custom serializer for just one property in Json.NET

Question

UPDATE Found the issue -- was inheriting from wrong class, needed to be JsonConverter.

I have a class that has a Location property of type System.Da

Answer 1

Use the JsonConverterAttribute on the property and define a custom converter-

for example, we have a property that comes in as a unix value (long int) and we serialize it to a .Net DateTime:

[JsonConverter(typeof(UnixTimeJsonConverter))]
public DateTime Requested { get; set; }

Answer 2

Turns out I just needed to inherit from JsonConverter instead of CustomCreationConverter, and everything else I was trying to change was OK all along.

I'm still not sure if there's a way to apply the JsonConverter fluently, but there is another way to apply the JsonConverter without referencing Json.NET in your domain/core project or marking up your domain classes with references to a peripheral library:

var jsonSerializer = new JsonSerializer();
jsonSerializer.Converters.Add(new DbGeographyConverter());
jsonSerializer.Serialize(jsonWriter, place);

Answer 3

You can add a custom serializer to a single attribute like this:

public class Comment
{
    public string Author { get; set; }

    [JsonConverter(typeof(NiceDateConverter))]
    public DateTime Date { get; set; }

    public string Text { get; set; }
}

public class NiceDateConverter : JsonConverter
{
    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        var date = value as DateTime;
        var niceLookingDate = date.ToString("MMMM dd, yyyy 'at' H:mm tt");
        writer.WriteValue(niceLookingDate);
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        throw new NotImplementedException("Unnecessary because CanRead is false. The type will skip the converter.");
    }

    public override bool CanRead
    {
        get { return false; }
    }

    public override bool CanConvert(Type objectType)
    {
        return objectType == typeof(DateTime);
    }
}

Then, when you serialize your object with JsonConvert.SerializeObject(), the custom serializer will be used for the Date property.