using System;

using System.Text.Json;

using System.Text.Json.Serialization;

​

for (int n = 0; n < 25; n++)

{

    TaxType? value = null;

    try

    {

        value = JsonSerializer.Deserialize<OrderInfo>("{ \"TaxType\": " + n + " }").TaxType;

    }

    catch {}

    Console.WriteLine($"{n}: {value}");

}

​

public class OrderInfo

{

    public TaxType TaxType { get; set; }

}

​

[CheckedEnum]

public enum TaxType : byte

{

    None = 0,

    GSTCanada = 5,

    HSTOntario = 13,

    HSTOther = 15

}

​

public class CheckedEnumAttribute : JsonConverterAttribute { public CheckedEnumAttribute() : base(typeof(CheckedEnumConverterFactory)) { } }

​

public class CheckedEnumConverterFactory : JsonConverterFactory

{

    public override bool CanConvert(Type typeToConvert)

        => typeToConvert.IsEnum;

​

    public override JsonConverter CreateConverter(Type typeToConvert, JsonSerializerOptions options)

        => (JsonConverter)Activator.CreateInstance(typeof(CheckedEnumConverter<>).MakeGenericType(typeToConvert));

}

​

public class CheckedEnumConverter<T> : JsonConverter<T> where T: struct, Enum

{

    static readonly TypeCode typeCode = Type.GetTypeCode(typeof(T));

​

    public override T Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)

    {

        T value = (T)(object)(typeCode switch

        {

            TypeCode.SByte => reader.GetSByte(),

            TypeCode.Byte => reader.GetByte(),

            TypeCode.Int16 => reader.GetInt16(),

            TypeCode.UInt16 => reader.GetUInt16(),

            TypeCode.Int32 => reader.GetInt32(),

            TypeCode.UInt32 => reader.GetUInt32(),

            TypeCode.Int64 => reader.GetInt64(),

            TypeCode.UInt64 => reader.GetUInt64()

        });

        if (!Enum.IsDefined(value)) throw new Exception($"Value {value} is invalid!");

        return value;

    }

​

    public override void Write(Utf8JsonWriter writer, T value, JsonSerializerOptions options)

    {

        if (!Enum.IsDefined(value)) throw new Exception($"Value {value} is invalid!");

        if (typeCode == TypeCode.UInt64)

            writer.WriteNumberValue((ulong)(object)value);

        else

            writer.WriteNumberValue(Convert.ToInt64(value));

    }

}