json to c# deserialization

Question

I'm looking how can I add cars to some list by their color. This is json file, and I've used json2csharp to generate classes.

I would like to use better way then checking every single car, and list of their colors. That is horrible if I have 40 cars for example.

json

    {
       "cars":[
          {
             "bmw":{
                "color":[
                   "blue",
                   "red"
                ]
             },
             "price":5
          },
          {
             "audi":{
                "color":[
                   "blue",
                   "yellow",
                   "white"
                ]
             },
             "price":7
          },
          {
             "nil":"nil"
          },
          {
             "peugeot":{
                "color":[
                   "blue",
                   "red",
                   "yellow",
                   "orange"
                ]
             },
             "price":12
          },
          {
             "ferrari":{
                "color":[
                   "blue",
                   "yellow",
                   "orange"
                ]
             },
             "price":12
          }
       ]
    }

code

public class Bmw
{
    public List<string> color { get; set; }
}

public class Audi
{
    public List<string> color { get; set; }
}

public class Peugeot
{
    public List<string> color { get; set; }
}

public class Ferrari
{
    public List<string> color { get; set; }
}

public class Car
{
    public Bmw bmw { get; set; }
    public int price { get; set; }
    public Audi audi { get; set; }
    public string nil { get; set; }
    public Peugeot peugeot { get; set; }
    public Ferrari ferrari { get; set; }
}

public class RootObject
{
    public List<Car> cars { get; set; }
}

using (StreamReader r = new StreamReader("carDB.json"))
            {
                string json = r.ReadToEnd();

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

                foreach(Car c in car.cars)
                {

                }

            }

Answer 1

You can achieve it by using System.Reflection library which adds performance penalty to some extent, but I suppose code isn't performance critical, so you'll be fine.

First of all, you need to create an interface:

public interface ICar
{
    List<string> color { get; set;}
}

Car classes should implement that interface:

public class Bmw : ICar
{
    public List<string> color { get; set; }
}

After that, you can traverse Car object by filtering out properties which type implements ICar interface.

RootObject root = JsonConvert.DeserializeObject<RootObject>(json);
foreach (var car in root.cars)
{
    var carProperties = car.GetType().GetProperties().Where(p => typeof(ICar).IsAssignableFrom(p.PropertyType));
    foreach (var carType in carProperties)
    {
        var c = carType.GetValue(car);
        if (c != null)
        {
            var colors = ((ICar)c).color;
            //Do your thing...
        }
    }
}