将Json字符串反序列化为自定义.Net对象

Question

I have very big plain json from server with format like this

{ "A": 1, "B" : 2, "C" : 3 }

I can't change format.

But instead of making one megaclass

public class MegaClass
{
    public int A;
    public int B;
    public int C;
}

I want to group some properties to another object, like this

public class MegaClass
{
    public int A;
    public SetOfVariables1 Set1;
}

public class SetOfVariables1
{
     public int B;
     public int C;
}

Is there way to make this work?

Answer 1

The bad news is, I would guess that you can't make that dynamicly. The good news is, that you can handle the deserialization yourself and generate from there your object.

I guess you are doing this to get a nicer structure, but be aware that you have to write your own serializer if you want to get the object back into its original structure.

I have found two options to achieve the result you are trying to get. I am no pro when it comes to Json.NET, in fact its fairly new to me.

Here Comes the code:

class Program
{
    static void Main(string[] args)
    {
        String json = "{ 'A': 1, 'B' : 2, 'C' : 3 }";
        var classA = JsonConvert.DeserializeObject<MegaClass>(json,new AConverter());
        var classA2 = JsonConvert.DeserializeObject<MegaClass2>(json);
    }

    public class MegaClass2
    {
        public int A { get; set; }
        public SetOfVariables SetOfVariables1 { get; set; }

        public MegaClass2()
        {
            _additionalData = new Dictionary<string, JToken>();
            SetOfVariables1 = new SetOfVariables();
        }

        [JsonExtensionData]
        private IDictionary<string, JToken> _additionalData;

        [OnDeserialized]
        private void OnDeserialized(StreamingContext context)
        {
            int b = (int)_additionalData["B"];
            int c = (int)_additionalData["C"];

            SetOfVariables1.B = b;
            SetOfVariables1.C = c;
        }
    }

    public class MegaClass
    {
        public int A { get; set; }
        public SetOfVariables SetOfVariables1 { get; set; }
    }

    public class SetOfVariables
    {
        public int B { get; set; }
        public int C { get; set; }
    }

    public class AConverter : CustomCreationConverter<MegaClass>
    {
        public override MegaClass Create(Type objectType)
        {
            throw new NotImplementedException();
        }

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            dynamic cl = serializer.Deserialize(reader);
            var classA = new MegaClass();
            classA.A = cl.A;
            var classB = new SetOfVariables();
            classB.B = cl.B;
            classB.C = cl.C;
            classA.SetOfVariables1 = classB;
            return classA;
        }
    }
}

So here is the descritption: The first option uses the CustomCreationConverter. We deserialize the object into its original representation and create from there a new one.

The second option seems to initialize our object after it was deserialized. The _additionalData is set by the framework and we simply use it to fill our object.

I saw the first option been used to create different objects according to the json provided. For example if you have a class A and Class B and both extend Class C then you can decide in the overriden Create method which object to deserialize.

The first option is inspired by the Json.NET documentation