using System;

using System.Text.Json;

using System.Text.Json.Serialization;

public class Program

{

    public static void Main()

    {

        string jsonOne = @"{ ""values"": ""abc"" }";

        TestClass jsonObjOne = JsonSerializer.Deserialize<TestClass>(jsonOne);

        Console.WriteLine(JsonSerializer.Serialize(jsonObjOne.StringValue));

        Console.WriteLine("---");

        string jsonTwo = @"{ ""values"": [1,2,3] }";

        TestClass jsonObjTwo = JsonSerializer.Deserialize<TestClass>(jsonTwo);

        Console.WriteLine(JsonSerializer.Serialize(jsonObjTwo.IntegerValues));

    }

}

​

    public class TestClassConverter : JsonConverter<TestClass>

    {

        public override TestClass Read(

            ref Utf8JsonReader reader,

            Type typeToConvert,

            JsonSerializerOptions options)

            {

                TestClass value = new TestClass();

​

                JsonElement root = JsonElement.ParseValue(ref reader);

                JsonElement values = root.GetProperty("values");

​

                value.values = values;

​

                switch (values.ValueKind)

                {

                    case JsonValueKind.String:

                        value.StringValue = values.ToString();

                        break;

​

                    case JsonValueKind.Array:

                        value.IntegerValues = JsonSerializer.Deserialize<int[]>(values);

                        break;

​

                    default:

                        throw new JsonException("Unsupported values type");

                }

​

                return value;

            }

​

​

        public override void Write(

            Utf8JsonWriter writer,

            TestClass value,

            JsonSerializerOptions options) =>

                throw new NotImplementedException();

    }

​

[JsonConverter(typeof(TestClassConverter))]

public class TestClass

{

    [JsonInclude]

    [JsonPropertyName("values")]

    public JsonElement? values { get; set; } = null; //this field should either be a string or an array.  nothing else.

    [JsonIgnore]

    public string StringValue { get; set; }

    [JsonIgnore]

    public int[] IntegerValues { get; set; }

​

}