Serializing Json.Net (JsonConverter.WriteJson)

Question

I use the fantastic Newtonsoft json.Net library (version 4.5.7.15008) for serialization and deserialization.

I would like to:

• Ignore the .Databag property when serializing.
• Configure JSON. First get the default JSON, change it and write the changed JSON to the result.

These are my classes:

 public interface ISimpleDatabag { string Databag { get; set; } } [JsonConverter(typeof(JsonDataBagCreationConverter<Department>))] public class Department : ISimpleDatabag { [JsonIgnoreAttribute] public string Databag { get; set; } public string Name { get; set; } public Telephone[] Phones { get; set; } } [JsonConverter(typeof(JsonDataBagCreationConverter<Telephone>))] public class Telephone : ISimpleDatabag { [JsonIgnoreAttribute] public string Databag { get; set; } public string Name { get; set; } public string AreaCode { get; set; } public string Number { get; set; } } public class JsonDataBagCreationConverter<T> : JsonConverter where T : ISimpleDatabag, new() { // Json.Net version 4.5.7.15008 public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer) { // problem 1 string jsonAsDefault = ""; // The json that would have been written have I not overridden WriteJson. How? // problem 1.a: Ignore the Databag property when writing the json. string myChangedJson = jsonAsDefault + "WhatEverIWant"; // problem 2 // Write myChangedJson to the resulting json string instead of jsonAsDefault // try //serializer.ReferenceLoopHandling = ReferenceLoopHandling.Serialize; // Otherwise self referencing loop detected, but then... // JObject jobj = JObject.FromObject(value, serializer); //... Stack overflow // jobj.WriteTo(writer); // try // writer.WriteValue(value); // "Unsupported type: Department // try //serializer.ReferenceLoopHandling = ReferenceLoopHandling.Serialize; // Otherwise self referencing loop detected, but then... // serializer.Serialize(writer, value); // ...Stack overflow // try // base.WriteJson(writer, value, serializer); base class is abstract } protected T Create(Type objectType, JObject jsonObject) { return new T(); } public override bool CanConvert(Type objectType) { return typeof(T).IsAssignableFrom(objectType); } public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer) { var jsonObject = JObject.Load(reader); var target = Create(objectType, jsonObject); serializer.Populate(jsonObject.CreateReader(), target); // Will call this function recursively for any objects that have JsonDataBagCreationConverter as attribute ((ISimpleDatabag)target).Databag = jsonObject.ToString(); // This is where custom data is stored in databag return target; } } public class IgnoreDataBagContractResolver : DefaultContractResolver { protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization) { JsonProperty property = base.CreateProperty(member, memberSerialization); if (property.PropertyName.ToLower() == "databag") { property.Ignored = true; return property; } return property; } } 

And the call:

 public Form1() { InitializeComponent(); string jsonInput = "{\"Name\": \"Seek4\" , \"CustomDepartmentData\": \"This is custom department data\", \"Phones\":[ {\"Name\": \"A\", \"AreaCode\":444, \"Number\":11111111} ,{\"Name\": \"B\", \"AreaCode\":555, \"Number\":987987987}, {\"Name\": \"C\", \"AreaCode\":222, \"Number\":123123123, \"CustomPhoneData\": \"This is custom phone data\"} ] }"; Department objDepartment = JsonConvert.DeserializeObject<Department>(jsonInput); // Yes, it works well objDepartment.Name = "Seek4Cars"; string json = ToSeek4Json(objDepartment); // This is my problem: Ignore Databag property and control the output json for each property } public static string ToSeek4Json(object objectToConvertToJson) { JsonSerializerSettings serializerSettings = new JsonSerializerSettings(); IgnoreDataBagContractResolver contractResolver = new IgnoreDataBagContractResolver(); serializerSettings.ContractResolver = contractResolver; return JsonConvert.SerializeObject(objectToConvertToJson, Formatting.None, serializerSettings); }