How to serialize a dynamic object to a JSON string in dotnet core?

Question

I am passing a JSON payload to an API Controller, and one of the fields is dynamic because the field needs to be passed again as a JSON string to another API. The dotnet core 3.1 middle layer shouldn't be concerned with typing, as the payload will change.

This is the object that is passed into the API Controller:

    public class GitHubAction
    {
        [JsonProperty("Title")]
        public string Title { get; set; }

        [JsonProperty("Enabled")]
        [JsonConverter(typeof(BooleanParseStringConverter))]
        public bool Enabled { get; set; }

        [JsonProperty("Action")]
        [JsonConverter(typeof(ExpandoObjectConverter))]
        public dynamic Action { get; set; }
    }

Here is a picture of that dynamic object looks like in VSCode:

When I use JsonConvert.SerializeObject(x.Action); the string result isn't being properly converted, but instead serializes to ValueKind: "{\"ValueKind\":1}".

What I want to get is the action object value as a JSON string, which should look like "{"createRepository":{"onboarding":{"service":{"organization":"foo","repositoryName":"foo-2-service","description":"A test service."}}}}"

Is there a simple solution for serializing a dynamic object?

Within

Is this using Newtonsoft.Json, or System.Text.Json? – Janettjanetta

ValueKind is from System.Text.Json, but JsonConvert is from Newtonsoft. It's quite possible you can't mix the 2 here. Try using JsonSerializer.Serialize instead of JsonConvert.SerializeObject. – Nook

There is a property named ValueKind of JsonElement: JsonElement.ValueKind. So probably your dynamic Action is actually a JsonElement, can you confirm please? A minimal reproducible example showing the JSON and deserialization code would be ideal. – Instrumental

The payload coming into the controller is being serialized using System.Text.Json pretty sure. I am not wiring up Newtonsoft in Startup, but I am doing some internal stuff using Newtonsoft else where in the code. And yes, it is a JsonElement. The POCO object I have in the OP might be misleadning. – Within

Answer 1

I had the same problem and I fixed it this way

using System.Text.Json;

string serializedObject = JsonSerializer.Serialize(x.Action); //Instead of use JsonConvert.SerializeObject(x.Action);

Instead of Newtonsoft.Json you have to use System.Text.Json.

Balata

This doesn't appear to answer the question as System.Text.Json doesn't currently handle dynamic properties. – Diacaustic

This worked for me, and I am using dynamic properties – Gob

Answer 2

Use Newtonsoft.Json instead of default System.Text.Json

Add Microsoft.AspNetCore.Mvc.NewtonsoftJson package from NUGET and services.AddControllers().AddNewtonsoftJson() in Startup.cs => ConfigureServices()

Kathrinekathryn

Answer 3

You can use Newtonsoft.Json.Converters.ExpandoObjectConverter to help you with this.

dynamic action = new ExpandoObject();
action.YourProperty = new ...;
var converter = new ExpandoObjectConverter();
var jsonString = JsonConvert.SerializeObject(action, converter);

Paine

Answer 4

Try this

var jsonString=s.Action.ToString();

This will give you the json string

Traitorous

Answer 5

I had the same issue when parsing a property with the "object" type:

public Dictionary<string, object> Fields { get; set; }

When using Newtonsoft.Json I got a serialised object that contained values looking something like: "Custom.Createdbyuser":{"ValueKind":3}" instead of "Custom.Createdbyuser":"John Doe"

When I switched to System.Text.Json and used the JsonSerializer.Serialze() & JsonSerializer.Deserialize() that fixed the issue for me.

Gaddy

Answer 6

If you want to use Newtonsoft.Json then follow this instructions :

in using section use this :

using Newtonsoft.Json;

Then

string serializedObject = JsonConvert.SerializeObject(value);

and for Deserializing use :

var desrializedObject = JsonConvert.DeserializeObject<T>(serializedObject);

Duong