newtonsoft not deserializing double values in inner class correctly

Question

I'm working with .NET 5 and Api Controllers. In my startup class (ConfigureServices) I have the following:

services.AddControllers().AddNewtonsoftJson(x =>
            {
                x.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;
            });

Then I have a controller like this:

[HttpPost]
public async Task<ActionResult<Company>> PostCompany(Company company)
{
}

And Company is a class like this

public class Company : Entity
    {
        Coordinates coordinates;
        public int CompanyId { get; set; }
        public string Name { get; set; }
        public NpgsqlTypes.NpgsqlBox Bounds { get; set; }
        [NotMapped]
        public Coordinates Coordinates
        {
            get { return coordinates ?? new Coordinates(); } 
            set { coordinates = value; Bounds = new NpgsqlTypes.NpgsqlBox(coordinates.Top, coordinates.Right, coordinates.Bottom, coordinates.Left); }  
        }
    }

    public class Coordinates
    {
        public double Left { get; set; }
        public double Right { get; set; }
        public double Bottom { get; set; }
        public double Top { get; set; }
    }

From postman I send a POST with this body (Content-Type: application/json in the Headers)

{
   "companyId":0,
   "name":"company 1",
   "coordinates":{
      "left":2,
      "right":5,
      "bottom":43,
      "top":3
   }
}

name has the correct value but why coordinates in the parameter of the api controller is always 0 in all its values? Seems it's newtonsoft deserialization because if I use this

public async Task<ActionResult<Company>> PostCompany(Object company2)
{
    var jsonString = company2.ToString();
    Company company = JsonConvert.DeserializeObject<Company>(jsonString);
}

I see the coordinates values in the company2 but not when deserialized into company object (which has 0 for all the coordinates).

Any idea? Thanks in advance. Guillermo.

Also, generally speaking you would never post and receive the DB model via an API, read up on DTO (Data Transfer Object) — zaitsman, Sep 05 '21 at 04:25
In the getter for `Coordinates` you need to do `return coordinates ?? coordinates = new Coordinates();` because Json.NET never sets the value back after it is populated. For why see [this answer](https://stackoverflow.com/a/32493007/3744182) to [Why are all the collections in my POCO are null when deserializing some valid json with the .NET Newtonsoft.Json component](https://stackoverflow.com/q/32491966/3744182) which is basically the same problem, although it asks about JSON arrays rather than objects. — dbc, Sep 05 '21 at 05:14
Alternatively, if you don't want to modify the setter in that way, that you could apply `[JsonProperty(ObjectCreationHandling = ObjectCreationHandling.Replace)]` to `public Coordinates Coordinates` which will force `Coordinates` to be freshly allocated and set back during serialization. See [How to apply ObjectCreationHandling.Replace to selected properties when deserializing JSON?](https://stackoverflow.com/a/33746313/3744182) for a similar question. — dbc, Sep 05 '21 at 05:15
@dbc That made it work! thx! Please post it as an answer to selected as the correct one. — polonskyg, Sep 06 '21 at 00:54
@zaitsman the [NotMapped] it's not related, it's telling it's not going to be mapped in Entity Framework, removing it, of course, didn't fix it I completely agree domain classes never should be use there and DTOs should be, but this is something done by other and consumed by clients so I cannot change the interface until they fix it on their end or start doing other thing I don't want/have the time now. — polonskyg, Sep 06 '21 at 00:56

newtonsoft not deserializing double values in inner class correctly

0 Answers0