Deserialize JSON to nested C# Classes

Question

Below is a (slightly) stripped down response I get from a REST API upon successful creation of a new "job code" entry. I need to deserialize the response into some classes, but I'm stumped.

For reference, I'm using JSON.NET in .NET 3.5 (running in a SSIS script in SQL Server 2008 R2) to attempt my deserialization. Here's the JSON - which I obviously have no control over as it's coming from someone else's API:

{
   "results":{
      "jobcodes":{
         "1":{
            "_status_code":200,
            "_status_message":"Created",
            "id":444444444,
            "assigned_to_all":false,
            "billable":true,
            "active":true,
            "type":"regular",
            "name":"1234 Main Street - Jackson"
         },
         "2":{
            "_status_code":200,
            "_status_message":"Created",
            "id":1234567890,
            "assigned_to_all":false,
            "billable":true,
            "active":true,
            "type":"regular",
            "name":"4321 Some Other Street - Jackson"
         }
      }
   }
}

In my C# code, I do have a "JobCode" class defined which only partially maps the JSON values to properties - I'm not interested in all of the data that's returned to me:

[JsonObject]
class JobCode
{
    [JsonProperty("_status_code")]
    public string StatusCode { get; set; }
    [JsonProperty("_status_message")]
    public string StatusMessage { get; set; }
    [JsonProperty("id")]
    public string Id {get; set;}
    [JsonProperty("name")]
    public string Name { get; set; }

    //-------------------------------------------------------------------------------
    // Empty constructor for JSON serialization support
    //-------------------------------------------------------------------------------

    public JobCode() { }
}

I'm attempting to deserialize the data via this call:

newResource = JsonConvert.DeserializeObject<JobCode>(jsonResponse);

Where jsonResponse is the code outputted above.
When I execute the code, "newResource" always comes back as null - which is not unexpected because I know that there are actually multiple job codes in the data and this code is trying to deserialize it into a single JobCode object. I tried creating a new class called JobCodes that looks like this:

class JobCodes
{
    [JsonProperty("jobcodes")]
    public List<JobCode>_JobCodes { get; set; }
}

And then I tried calling this (JobCodes instead of JobCode):

newResource = JsonConvert.DeserializeObject<JobCodes>(jsonResponse);

But the issue persists - my return object is null. What's throwing me off, I think, is the presence of the "1" and "2" identifiers. I don't know how to account for their presence in my object design and/or usage of the JSON.NET class / property attributes like [JsonObject],[JsonProperty], etc.

When I run the JSON data through JSON2CSharp, it constructs some weird-looking classes, so that hasn't proven too effective. I've validated the JSON with several different validators and it all checks out–I just don't know what I'm missing here.

Ultimately, I'd like to return a List<JobCode> from the JSON data, but I'm stumped on what I need to do to make that happen.

Answer 1

Your problem is twofold:

1. You don't have a class defined at the root level. The class structure needs to match the entire JSON, you can't just deserialize from the middle.
2. Whenever you have an object whose keys can change, you need to use a Dictionary<string, T>. A regular class won't work for that; neither will a List<T>.

Make your classes like this:

class RootObject
{
    [JsonProperty("results")]
    public Results Results { get; set; }
}

class Results
{
    [JsonProperty("jobcodes")]
    public Dictionary<string, JobCode> JobCodes { get; set; }
}

class JobCode
{
    [JsonProperty("_status_code")]
    public string StatusCode { get; set; }
    [JsonProperty("_status_message")]
    public string StatusMessage { get; set; }
    [JsonProperty("id")]
    public string Id { get; set; }
    [JsonProperty("name")]
    public string Name { get; set; }
}

Then, deserialize like this:

RootObject obj = JsonConvert.DeserializeObject<RootObject>(json);

Working demo here