JObject & CamelCase conversion with JSON.Net

Question

How can I convert a generic JObject to camelCase plain json string? I've tried with JsonSerializerSettings but doesn't work (Newtonsoft.Json 4.5.11)

[Test]
public void should_convert_to_camel_case()
{
    var serializer = JsonSerializer.Create(new JsonSerializerSettings()
    {
        ContractResolver = new CamelCasePropertyNamesContractResolver()
    });

    var jo = new JObject();
    jo["CamelCase"] = 1;

    var stringWriter = new StringWriter();
    var writer = new JsonTextWriter(stringWriter);
    serializer.Serialize(writer,jo);

    var serialized = stringWriter.ToString();

    Assert.AreEqual("{\"camelCase\":1}", serialized);
}

UPDATE According to http://json.codeplex.com/workitem/23853 that cannot be done (tnx to @nick_w for the link)

score 52 · Answer 1 · answered Jan 26 '15 at 19:13

52

This question starts from a JObject and wants to work to a camel-cased JSON object. If you are actually starting from an object and want to get to a JObject that is already camelcased, then you can do this:

var serializer = new JsonSerializer()
{
    ContractResolver = new CamelCasePropertyNamesContractResolver()
};
var jo = JObject.FromObject(someDataContract, serializer);

The resulting 'jo' will be camelcased.

answered Jan 26 '15 at 19:13

Steve Benz

553
4
3

1

How can I perform the opposite: `JObject.Load(jsonReader)` by specifying the resolver? – Shimmy Weitzhandler Dec 07 '17 at 00:16
1

Tried this with `JObject` instance method `ToObject(serializer)` but it does not work – Andrii Feb 08 '19 at 12:32
1

JObject is not serialized, it is written "as is", so this answer isn't going to work. – Egor Pavlikhin May 27 '21 at 04:48

score 24 · Answer 2 · edited Apr 17 '18 at 03:19

According to this Json.NET issue, when serializing a JObject this way the contract resolver is ignored:

When serializing a JObject the contract resolvers seems to be ignored. Surely this is not how it is supposed to be?
Closed Jan 30, 2013 at 8:50 AM by JamesNK
That does make sense but it is too big a breaking change I'm afraid.

Inspired by the workaround on that page, you could do something like this:

var jo = new JObject();
jo["CamelCase"] = 1;

string json = JsonConvert.SerializeObject(jo);
var jObject = JsonConvert.DeserializeObject<ExpandoObject>(json);

var settings = new JsonSerializerSettings()
{
    ContractResolver = new CamelCasePropertyNamesContractResolver()
};

var serialized = JsonConvert.SerializeObject(jObject, settings);

Assert.AreEqual("{\"camelCase\":1}", serialized);

Edit:

Good point about the Dictionary<string, object>. So doing it this way skips the additional JsonConvert.SerializeObject, but it also mitigates the need for the ExpandoObject, which is important if you are using .NET 3.5.

Dictionary<string, object> jo = new Dictionary<string, object>();
jo.Add("CamelCase", 1);

var settings = new JsonSerializerSettings()
{
    ContractResolver = new CamelCasePropertyNamesContractResolver()
};

var serialized = JsonConvert.SerializeObject(jo, settings);

Assert.AreEqual("{\"camelCase\":1}", serialized);

don't think serialize + deserialize + serialize is too efficient. — Andrea Balducci, Feb 27 '13 at 11:47

score 6 · Answer 3 · answered Jun 25 '15 at 18:19

As of this May 8th, 2013 blog post by James Newton-King regarding the 5.0 release of Json.NET, this has been addressed with the addition of "DefaultSettings". The example from that page follows but read the page for details for 3rd party libraries.

// settings will automatically be used by JsonConvert.SerializeObject/DeserializeObject
JsonConvert.DefaultSettings = () => new JsonSerializerSettings
    {
    Formatting = Formatting.Indented,
    ContractResolver = new CamelCasePropertyNamesContractResolver()
    };

Employee e = new Employee
    {
    FirstName = "Eric",
    LastName = "Example",
    BirthDate = new DateTime(1980, 4, 20, 0, 0, 0, DateTimeKind.Utc),
    Department = "IT",
    JobTitle = "Web Dude"
    };

string json = JsonConvert.SerializeObject(e);
// {
//   "firstName": "Eric",
//   "lastName": "Example",
//   "birthDate": "1980-04-20T00:00:00Z",
//   "department": "IT",
//   "jobTitle": "Web Dude"
// }

rafiq J · Answer 4 · 2018-11-26T09:41:50.700

public static JsonSerializer FormattingData()
{
   var jsonSerializersettings = new JsonSerializer {
   ContractResolver = new CamelCasePropertyNamesContractResolver() };
   return jsonSerializersettings;
}


public static JObject CamelCaseData(JObject jObject) 
{   
   var expandoConverter = new ExpandoObjectConverter();
   dynamic camelCaseData = 
   JsonConvert.DeserializeObject(jObject.ToString(), 
   expandoConverter); 
   return JObject.FromObject(camelCaseData, FormattingData());

}

JObject & CamelCase conversion with JSON.Net

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