Newtonsoft.json ignore Json property attributes

Question

Newtonsoft.Json ignore JsonProperty attributes while serializing object to json in .NET Framework 4.5 legacy webapi project.

Properties in my class looks as simple as this:

using Newtonsoft.Json;

public class A
{

    [JsonProperty(PropertyName = "workflow")]
    public string Workflow { get; private set; }

}

Then i am executing serializing:

using Newtonsoft.Json;

var asJson = JsonConvert.SerializeObject(
    a,
    Formatting.None,
    new JsonSerializerSettings
    {
        NullValueHandling = NullValueHandling.Ignore
    });

And output looks like this:

{
    "Workflow": "18",
}

instead of:

{
    "workflow": "18"
},

Based on JsonProperty. My question is, why newtonsoft serializer ignore Jsonproperty attributes in .NET Framework 4.5 web api project?

You need to put the full json and full class, not just one property — Serge, Jul 04 '22 at 17:03
Thanks, but it is not valid, can you post a valid json pls, and you can not add property attribute to a class — Serge, Jul 04 '22 at 17:05
I can't reproduce the problem. Here's a complete piece of code that compiles (you have provided incomplete code...) https://gist.github.com/jskeet/b2a3738b426f6deaa0d073126c0dac8f The output is `{"workflow":"test"}`. — Jon Skeet, Jul 04 '22 at 17:13
I can't reproduce either, see https://dotnetfiddle.net/UYwntN. Two possibilities: 1) You are mixing version of Json.NET and the `[JsonProperty]` applied to your model is from a different DLL version that the one being used by the call to `JsonConvert.SerializeObject()`. 2) You are actually using System.Text.Json to serialize without realizing it. — dbc, Jul 04 '22 at 18:00
A third possibility to add to @dbc is that you are actually using `JsonPropertyName` which is for `System.Text.Json` but you are deserializing using JSON.Net — Charlieface, Jul 04 '22 at 19:47
Or 4) You have some [global default value for `JsonSerializerSettings`](https://www.newtonsoft.com/json/help/html/DefaultSettings.htm) that is interfering with `JsonPropertyAttribute.PropertyName` somehow. What is the value of `JsonConvert.DefaultSettings`? See: [Json.net global settings](https://stackoverflow.com/q/15066904/3744182). — dbc, Jul 04 '22 at 23:40

Serge · Accepted Answer · 2022-07-04T17:15:26.027

2

you examples are not valid, this is working for me

    var a = new A {Workflow="18"};

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


public class A
{
    [JsonProperty(PropertyName = "workflow")]
    public string Workflow { get;  set; }
}

result

{"workflow":"18"}

the same is with this class

public class A
{
    [JsonProperty(PropertyName = "workflow")]
    public string Workflow { get; private set; }
    
    public A(string workflow)
    {
        Workflow=workflow;
    }
}

edited Jul 04 '22 at 17:15

answered Jul 04 '22 at 17:10

Serge

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Yea but believe me, in my case it is not working. Do you have an idea what to check wehn these properties not working? – michasaucer Jul 04 '22 at 17:32
@michasaucer - *Yea but believe me, in my case it is not working.* -- then please [edit](https://stackoverflow.com/posts/72859929/edit) your question to share a [mcve]. That can't be your real code because your class `A` has no public setter and thus `Workflow` could never be set to `"18"`. See [ask]. Serge made a reasonable guess as to how to fix your example to make it work but it could be your real code is what is causing the problem. – dbc Jul 04 '22 at 18:02
1

@michasaucer The best thing is to post your original. You don't need to post all properties, just a couple would be enough. – Serge Jul 04 '22 at 18:42

Newtonsoft.json ignore Json property attributes

1 Answers1