deserializing child data collections into ienumerables using JSON.NET

Question

Current I have a project where I'm getting the following sample data ( I want to retrieve only the ids within this json string and stuff them into IEnumerables (explained below):

{
  "states": [
    {
      "id": "AL",
      "text": "Alabama (AL)"
    },
    {
      "id": "CO",
      "text": "Colorado (CO)"
    }
  ],
  "cities": [
    {
      "id": 71761,
      "text": "New Brockton, AL"
    },
    {
      "id": 74988,
      "text": "Nathrop, CO"
    }
  ],
  "zipCodes": []
}

Notice in the zipCodes, I am getting an empty set, so there is no "id" or "text".

I want to be able to create several IEnumerables from the properties found in this JSON string.

I created an object called Locations that looks like this:

public class Location
{
    public IEnumerable<string> States { get; set; }
    public IEnumerable<string> ZipCodes { get; set; }
    public IEnumerable<decimal> Cities { get; set; }
}

The best way I found to going about this approach is to do each data property one by one and convert, formValues is the json string:

JArray arrStates = (JArray)formValues["states"];
JArray arrCities = (JArray)formValues["cities"];
JArray arrZip = (JArray)formValues["zipCodes"];

and then set the properties in the location object as so:

Location loc = new Location();
loc.States = arrStates.Children().Select(m=>m["id"].Value<string>());
loc.ZipCodes = arrCities.Children().Select(m=>m["id"].Value<string>());
loc.Cities = arrZip.Children().Select(m=>m["id"].Value<string>());

I was wondering if there's a better way of doing this instead of doing all this code maintenance for whenever my json response adds a new property. In fact, I think there's going to be about ten more properties added to the json string.

I want it to be reduced down to where I could just update the Location object, and have the json automatically map to the properties that way. Or atleast a solution that has less maintenance than what I'm doing now.

Also I was wondering if JsonConvert.DeserializeObject would work in my case; but read that JSON.NET treats an IEnumerable as an array, so I'm stumped on this one.

score 1 · Accepted Answer · answered Feb 20 '14 at 16:27

JsonConvert.DeserializeObject would work in your case and it will have less maintenance than what you're doing now.

If you enter your json data to http://json2csharp.com, below is the generated class definition that you can use, I renamed RootObject to Location

public class State
{
    public string id { get; set; }
    public string text { get; set; }
}

public class City
{
    public int id { get; set; }
    public string text { get; set; }
}

public class Location
{
    public List<State> states { get; set; }
    public List<City> cities { get; set; }
    public List<object> zipCodes { get; set; }
}

This is how you deserialize the json data into Location

string jsonData = ...; // set the json data here

var location = JsonConvert.DeserializeObject<Location>(jsonData);

You can enumerate through the nested properties to get the ids, for example location.states[0].id will return "AL" and location.cities[1].id will return 74988.

If there's a new property in the json data, let's say it's named countries with id and text like in states, you can create a new Country class

public class Country
{
    public string id { get; set; }
    public string text { get; set; }
}

and add countries property to Location class

public class Location
{
    public List<State> states { get; set; }
    public List<City> cities { get; set; }
    public List<object> zipCodes { get; set; }
    public List<Country> countries { get; set; }
}

deserializing child data collections into ienumerables using JSON.NET

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