JSON.NET Serialize DateTime.MinValue as null

Question

I\'d like DateTime fields that are set to DateTime.MinValue returned by my Web API to be serialized to NULL instead of \"0001-01

Answer 1

Custom DateTime Json Converter

public class DateTimeConverter : JsonConverter
{   
    public override void WriteJson(JsonWriter jsonWriter, object inputObject,JsonSerializer jsonSerializer)
    {
        // Typecast the input object
        var dateTimeObject = inputObject as DateTime?;

        // Set the properties of the Json Writer
        jsonWriter.Formatting = Newtonsoft.Json.Formatting.Indented;

        if(dateTimeObject == DateTime.MinValue)
            jsonWriter.WriteValue((DateTime?)null);
        else
            jsonWriter.WriteValue(dateTimeObject);
    }


    public override object ReadJson(JsonReader reader,
        Type objectType,
        object existingValue,
        JsonSerializer serializer)
    {
        DateTime? readValue = reader.ReadAsDateTime();

        return (readValue == null) ? DateTime.MinValue : readValue;     

    }


    public override bool CanConvert(Type objectType)
    {
        return typeof(DateTime?).IsAssignableFrom(objectType);
    }
}

Usage:

public class DateTest
{
    [JsonConverterAttribute(typeof(DateTimeConverter))]
    public DateTime? MyDateTime { get; set;}

    [JsonConverterAttribute(typeof(DateTimeConverter))]
    public DateTime? MyDateTime1 { get; set; }
}

void Main()
{
    DateTest dateTest = new DateTest 
    { 
      MyDateTime = DateTime.MinValue, 
      MyDateTime1 = DateTime.MaxValue
    };

    Console.WriteLine(JsonConvert.SerializeObject(dateTest));
}

Result:

{
  "MyDateTime": null,
  "MyDateTime1": "9999-12-31T23:59:59.9999999"
}