.NET Core 3.0 JsonSerializer.Deserialize return type dynamic objects

.NET Core 3.0 JsonSerializer.Deserialize to dynamic object

Because the official does not support the dynamic type of the returned object, only own handwriting a temporary tested no problem, still imperfect in some places you can take at your own modifications.

.net Core3 no support

Add the Json Converter

add using:

• using System.Text.Json;
• using System.Text.Json.Serialization;

    /// <summary>
    /// Temp Dynamic Converter
    /// by:[email protected]
    /// </summary>
    public class DynamicJsonConverter : JsonConverter<dynamic>
    {
        public override dynamic Read(ref Utf8JsonReader reader,
            Type typeToConvert,
            JsonSerializerOptions options)
        {

            if (reader.TokenType == JsonTokenType.True)
            {
                return true;
            }

            if (reader.TokenType == JsonTokenType.False)
            {
                return false;
            }

            if (reader.TokenType == JsonTokenType.Number)
            {
                if (reader.TryGetInt64(out long l))
                {
                    return l;
                }

                return reader.GetDouble();
            }

            if (reader.TokenType == JsonTokenType.String)
            {
                if (reader.TryGetDateTime(out DateTime datetime))
                {
                    return datetime;
                }

                return reader.GetString();
            }

            if (reader.TokenType == JsonTokenType.StartObject)
            {
                using JsonDocument documentV = JsonDocument.ParseValue(ref reader);
                return ReadObject(documentV.RootElement);
            }
            // Use JsonElement as fallback.
            // Newtonsoft uses JArray or JObject.
            JsonDocument document = JsonDocument.ParseValue(ref reader);
            return document.RootElement.Clone();
        }

        private object ReadObject(JsonElement jsonElement)
        {
            IDictionary<string, object> expandoObject = new ExpandoObject();
            foreach (var obj in jsonElement.EnumerateObject())
            {
                var k = obj.Name;
                var value = ReadValue(obj.Value);
                expandoObject[k] = value;
            }
            return expandoObject;
        }
        private object? ReadValue(JsonElement jsonElement)
        {
            object? result = null;
            switch (jsonElement.ValueKind)
            {
                case JsonValueKind.Object:
                    result = ReadObject(jsonElement);
                    break;
                case JsonValueKind.Array:
                    result = ReadList(jsonElement);
                    break;
                case JsonValueKind.String:
                    //TODO: Missing Datetime&Bytes Convert
                    result = jsonElement.GetString();
                    break;
                case JsonValueKind.Number:
                    //TODO: more num type
                    result = 0;
                    if (jsonElement.TryGetInt64(out long l))
                    {
                        result = l;
                    }
                    break;
                case JsonValueKind.True:
                    result = true;
                    break;
                case JsonValueKind.False:
                    result = false;
                    break;
                case JsonValueKind.Undefined:
                case JsonValueKind.Null:
                    result = null;
                    break;
                default:
                    throw new ArgumentOutOfRangeException();
            }
            return result;
        }

        private object? ReadList(JsonElement jsonElement)
        {
            IList<object?> list = new List<object?>();
            foreach (var item in jsonElement.EnumerateArray())
            {
                list.Add(ReadValue(item));
            }
            return list.Count == 0 ? null : list;
        }
        public override void Write(Utf8JsonWriter writer,
            object value,
            JsonSerializerOptions options)
        {
           // writer.WriteStringValue(value.ToString());
        }
    }

How to Use?

var serializerOptions = new JsonSerializerOptions
{
    Converters = { new DynamicJsonConverter() }
};
return JsonSerializer.Deserialize<dynamic>("{OK:"200"}", serializerOptions);