将ASP.NET Web API 2中值类型(C#)的.MinValue序列化为null

public class ValueTypeConverter : JsonConverter
{
    private static List<Type> SupportedTypes = new List<Type>
    {
        typeof(short),typeof(int),typeof(long),typeof(float),typeof(double),typeof(decimal),typeof(DateTime)
    };

    private static Dictionary<Type,object> MinValues;

    static ValueTypeConverter()
    {
        MinValues = new Dictionary<Type,object>();

        foreach (Type type in SupportedTypes)
        {
            MinValues.Add(type,GetMinValue(type));
        }
    }

    public override object ReadJson(
        JsonReader reader,Type objectType,object existingValue,JsonSerializer serializer)
    {
        object value = reader.Value;

        value = value ?? MinValues[objectType];
        value = Convert.ChangeType(value,objectType);

        return value;
    }

    public override bool CanConvert(Type objectType)
    {
        return MinValues.ContainsKey(objectType);
    }

    public override void WriteJson(
        JsonWriter writer,object value,JsonSerializer serializer)
    {        
        object minValue = MinValues[value.GetType()];

        if (object.Equals(value,minValue))
        {
            value = null;
        }

        writer.WriteValue(value);
    }

    private static object GetMinValue(Type objectType)
    {
        FieldInfo minValueFieldInfo = objectType.GetField("MinValue");

        return minValueFieldInfo.GetValue(null);
    }
}

用法：

var settings = new JsonSerializerSettings
{
    Converters = new[] { new ValueTypeConverter() }
};

string json = JsonConvert.SerializeObject(obj,settings);

示例：https://dotnetfiddle.net/WPhJr5