c# - JSON deserialize to constructed protected setter array

Question

I use Newtonsoft JSON to serialize/deserialize my objects. One of those contains an array with a protected setter because the constructor build the array itself and only the members are manipulated.

This can be serialized without problem but when it comes to deserialization the property it is ignored because it is not public. I tried a custom converter with it is also not called because it is not public.

This is a minimized example:

public static class TestCoordsDeserialization
{
    private class Coords
    {
        public Double X { get; set; }
        public Double Y { get; set; }
        public Double Z { get; set; }
        public Double A { get; set; }
    }

    private class Engine
    {
        public string Text { get; set; }
        public int Id { get; set; }
        public Coords[] Outs { get; protected set; }

        public Engine()
        {
            this.Outs = new Coords[3];
            for (int i = 0; i < this.Outs.Length; i++)
            {
                this.Outs[i] = new Coords();
            }
        }
    }

    public static void Test()
    {
        Engine e = new Engine();
        e.Id = 42;
        e.Text = "MyText";
        e.Outs[0] = new Coords() { A = 0, X = 10, Y = 11, Z = 0 };
        e.Outs[1] = new Coords() { A = 0, X = 20, Y = 22, Z = 0 };
        e.Outs[2] = new Coords() { A = 0, X = 30, Y = 33, Z = 0 };
        string json = JsonConvert.SerializeObject(e);
        Console.WriteLine(json); //{"Text":"MyText","Id":42,"Positions":{"Test":9,"Outs":[{"X":10.0,"Y":11.0,"Z":0.0,"A":0.0},{"X":20.0,"Y":22.0,"Z":0.0,"A":0.0},{"X":30.0,"Y":33.0,"Z":0.0,"A":0.0}]}}
        Engine r = JsonConvert.DeserializeObject<Engine>(json);
        double value = r.Outs[1].X; // should be '20.0'
        Console.WriteLine(value);
        Debugger.Break();
    }
}

How can I make value to be 20.0?

Answer 1

Mark Outs with the [JsonProperty] attribute:

    private class Engine
    {
        public string Text { get; set; }
        public int Id { get; set; }
        [JsonProperty]  // Causes the protected setter to be called on deserialization.
        public Coords[] Outs { get; protected set; }

        public Engine()
        {
            this.Outs = new Coords[3];
            for (int i = 0; i < this.Outs.Length; i++)
            {
                this.Outs[i] = new Coords();
            }
        }
    }