Serialize A Dynamic Object To A JSON String In .Net Core

I am working on an application where I am passing a JSON payload to an API Controller. One of the JSON fields is dynamic because it needs to be passed again as a JSON string to another third-party API. I'm using .NET Core 6. Let's see how we can achieve this.

When passing a JSON payload to an API Controller with fields like Id, Name, Email, Cost, and a dynamic field named FeedDetail, I encountered an issue. Upon using JsonConvert.SerializeObject(Model.FeedDetail), the resulting string is not being properly converted. Instead, it serializes to ValueKind: "{\"ValueKind\":1}. What I actually want is to get the value of the action object as a JSON string.

[ApiController]
    [Route("api/[controller]")]
    public class SocialMediaController : ControllerBase
    {
        [HttpPost]
        public IActionResult CreateFeed([FromBody] CreateFeedDTO model)
        {
            try
            {
                // Serialize the FeedDetail property to a JSON string
                string feedDetailJson = JObject.FromObject(model.FeedDetail).ToString();

                // Now you can use feedDetailJson as needed

                return Ok("FeedDetail successfully serialized to JSON string: " + feedDetailJson);
            }
            catch (Exception ex)
            {
                return StatusCode(500, "An error occurred: " + ex.Message);
            }
        }
    }

    public class CreateFeedDTO
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Email { get; set; }
        public decimal Cost { get; set; }
        public dynamic FeedDetail { get; set; }
    }

using System.Text.Json;

string serializedObject = JsonSerializer.Serialize(model.CreateFeedDTO); 

First, ensure you have the Newtonsoft.Json package installed:

dotnet add package Newtonsoft.Json

Then, in your controller, define the HTTP POST endpoint:

using Newtonsoft.Json;

[HttpPost]
public IActionResult Post([FromBody] dynamic data)
{
    try
    {
        // Serialize dynamic object to JSON string
        string jsonString = JsonConvert.SerializeObject(data);

        // Perform database entry with the JSON string
        

        return Ok("Entry successfully added to database.");
    }
    catch (Exception ex)
    {
        return StatusCode(500, "An error occurred: " + ex.Message);
    }
}

In above code, we accept a `dynamic` parameter named `data` in the POST method. We then directly serialize this `dynamic` object into a JSON string using Newtonsoft.Json's `JsonConvert.SerializeObject()` method and then we can perform the database entry operation with this JSON string.

First, we need to use the Newtonsoft.Json package, which is commonly used for JSON serialization in .NET applications. If you haven't already installed it, you can do so via NuGet:

dotnet add package Newtonsoft.Json

Once installed, you can use the following code snippet to serialize a dynamic object:

using Newtonsoft.Json;

dynamic myDynamicObject = new ExpandoObject();
myDynamicObject.Name = "John";
myDynamicObject.Age = 30;

string jsonString = JsonConvert.SerializeObject(myDynamicObject);

In above code , we first create a dynamic object using the `ExpandoObject` class. We then add properties (`Name` and `Age` in this case) to this dynamic object. Finally, we use `JsonConvert.SerializeObject()` method from Newtonsoft.Json to serialize the dynamic object into a JSON string.