How to serialize only not null properties in derived class in Json.Net

Question

Entity objects needs converted to string to store them in log file for human reading. Properties may added to derived entities at runtime. Serialize is defined in entity base class. I triesd code below but it returns properties with null values also. Since many properties have null values, it makes logs difficult to read.

Hoq to serialize only not-null properties ? I tried also

        var jsonSettings = new JsonSerializerSettings()
        {
            DefaultValueHandling = DefaultValueHandling.Ignore,
            Formatting = Formatting.Indented,
            TypeNameHandling= TypeNameHandling.All
        };
        return JsonConvert.SerializeObject(this, GetType(), jsonSettings);

this serializes only EntityBase class properties as confirmed in newtonsoft json does not serialize derived class properties

public class EntityBase {

        public string Serialize()
        {
            var s = new System.Web.Script.Serialization.JavaScriptSerializer();
            s.Serialize(this);

        }
     }

public class Customer: EntityBase {
  public string Name, Address;
  }

testcase:

  var cust= new Customer() { Name="Test"};
  Debug.Writeline( cust.Serialize());

Observed: result contains "Address": null

Expected: result shoud not contain Address property.

ASP.NET/Mono MVC4, .NET 4.6 are used

this might help you http://stackoverflow.com/questions/8513042/json-net-serialize-deserialize-derived-types — ltiveron, Oct 07 '16 at 14:19
I tried `TypeNameHandling= TypeNameHandling.All` according to this. Also tried to pass type ussing `JsonConvert.SerializeObject(this, GetType(), jsonSettings)` but child class properties are still not serialized. — Andrus, Oct 07 '16 at 14:49
What do you mean by *Properties may added to derived entities at runtime.*? Do you really mean *runtime*? If so, is your base class inheriting from `ExpandoObject` or something similar? — dbc, Oct 07 '16 at 17:15
Json.NET seems to work fine. `Name` is serialized while `Address` is not. See https://dotnetfiddle.net/Xljh8U — dbc, Oct 07 '16 at 17:28
Your fiddle works OK but in MVC controller similar code does not return any property. No idea why — Andrus, Oct 07 '16 at 21:27

score 7 · Answer 1 · answered Jun 08 '17 at 16:49

You can create your own serializer to ignore null properties.

            JsonConvert.SerializeObject(
                object, 
                Newtonsoft.Json.Formatting.None, 
                new JsonSerializerSettings
                {
                    NullValueHandling = NullValueHandling.Ignore
                });

How to serialize only not null properties in derived class in Json.Net

1 Answers1