使用Newtonsoft Json.NET仅序列化派生类型

Question

Is there any JsonSerializerSettings available for serializing only the derived type.

for example consider i have below two class. When I am serializing Employee object the the result json should only contains the properties of employee not the person class.

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

public class Employee : Person
{
    public DateTime JoiningDate { get; set; }
    public string EmployeeId { get; set;}
}

Answer 1

Questions like those usually reflect an issue with model design, however, one way to do what you want to do is to get rid of the inheritance; you could try something like converting your object to dynamic and then serialize the dynamic object :

class MyJson
{
    public static string SerializeObject<T>(T obj, bool ignoreBase)
    {
        if (!ignoreBase)
        {
            return JsonConvert.SerializeObject(obj);
        }

        var myType = typeof(T);
        var props = myType.GetProperties().Where(p => p.DeclaringType == myType).ToList();

        var x = new ExpandoObject() as IDictionary<string, Object>;
        props.ForEach(p => x.Add(p.Name, p.GetValue(obj, null)));

        return JsonConvert.SerializeObject(x);
    }
}

call it like

MyJson.SerializeObject<Employee>(e, true)

This way you can use it for any type and filter the properties to serialize however you wish in the helper class. For example, you can check the property attributes and decided if it should be added to the dynamic object.

Answer 2

You can use a custom JsonConverter for that purpose. Please see below for a basic version for your purpose.

public class PersonConverter : JsonConverter
{
    public override bool CanConvert(Type objectType)
    {
        if (objectType == typeof(Employee))
            return true;

        return false;
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        return "";
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        JToken t = JToken.FromObject(value);

        if (t.Type != JTokenType.Object)
        {
            t.WriteTo(writer);
        }
        else
        {
            JObject o = (JObject)t;

            o.Remove("Name"); //currently the property name is hardcoded. You could enhance this to remove any property you like

            o.WriteTo(writer);
        }
    }
}

After creating your JsonConverter you can use that during deserialization like below,

var des = JsonConvert.SerializeObject(e, new PersonConverter());
//e is the Person instance we want to convert and PersonConverter is the custom converter
//we use of serialization

Please see this link for more information on this