json.net does not serialize properties from derived class

Question

I'm using JSON.NET 6.0.1. When I use the SerializeObject method to serialize an object of my derived class, it serializes properties from base class only. Here is the code snippet:

string v = JsonConvert.SerializeObject(
                service, 
                Formatting.Indented, 
                new JsonSerializerSettings()
                {
                    TypeNameHandling = TypeNameHandling.All
                });

base class:

[DataContract]
public abstract partial class DataEntity : IDataEntity, INotifyPropertyChanging, INotifyPropertyChanged
{
    ...
}

derived class:

[Table(Name = "dbo.mytable")]
public sealed class mytable : DataEntity
{
    ...
}

Am I missing something?

Brian Rogers · Accepted Answer · 2020-11-04 22:39:28Z

32

Yes, you are missing the [DataContract] attribute on the derived class. You also need to add [DataMember] to any properties or fields that you want serialized, if you haven't already added them. Json.Net was changed in version 5.0 release 1 (April 2013) such that the [DataContract] attribute is not inherited.

Note that if you remove all instances of [DataContract] and [DataMemeber] from your classes, Json.Net behaves differently: in that case, the default behavior is for Json.Net to serialize all public properties, both in the base and derived classes.

edited Nov 4, 2020 at 22:39

answered Feb 28, 2014 at 3:42

Brian Rogers

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8 Comments

JoelFan Over a year ago

Is there any way to change this behavior?

Brian Rogers Over a year ago

@JoelFan You'll have to be more specific.

JoelFan Over a year ago

I want to be able to tell JsonConvert.SerializeObject to serialize all the properties, regardless of any attributes. I have a class that derives from a class marked [DataContract], but my derived class is not marked. As a result, only the base class's properties are being serialized.

Brian Rogers Over a year ago

@JoelFan See Configure JSON.NET to ignore DataContract/DataMember attributes

Brian Rogers Over a year ago

@JoãoPortela I've removed the quote since it seems to be causing confusion for people. The answer is still useful without it.

|

Ray · Accepted Answer · 2018-06-20 14:36:05Z

4

Adding the attribute [JsonObject(MemberSerialization.OptOut)] to your derived class will include all its public members to be serialized.

[Table(Name = "dbo.mytable")]
[JsonObject(MemberSerialization.OptOut)]
public sealed class mytable : DataEntity
{
    ...
}

Alternatively, if you only want certain properties of your derived class to be serialized you can add the attribute [JsonProperty] to each one (This would be equivalent of adding [DataMember] to each property along with [DataContract] on the class).

answered Jun 20, 2018 at 14:36

Ray

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1 Comment

Luis Gouveia Over a year ago

Fantastic @Ray, thanks! I don't understand why did is not the accepted/most upvoted answer, as it is well commented on the web that TypeNameHandling.All brings security issues. Just a side note, if your derived class is Internal, just like mine, the [JsonObject(MemberSerialization.OptOut)] will not work. You'll have to use the [JsonProperty] on each base class member. It works just fine though!

masteroleary · Accepted Answer · 2016-04-27 16:34:04Z

-2

JsonConvert.SerializeObject was only return {} for me. I found that I needed to add a new constructor to the class before it serialized properly.

answered Apr 27, 2016 at 16:34

masteroleary

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