SmartEnum/src/SmartEnum.SystemTextJson/SmartEnumNameConverter.cs at 48abb916bb83b7c76c8cf5c1f00db55bf52a2202 · ardalis/SmartEnum · GitHub

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namespace Ardalis.SmartEnum.SystemTextJson
{
    using System;
    using System.Text.Json;
    using System.Text.Json.Serialization;

    /// <summary>
    ///
    /// </summary>
    /// <typeparam name="TEnum"></typeparam>
    /// <typeparam name="TValue"></typeparam>
    public class SmartEnumNameConverter<TEnum, TValue> : JsonConverter<TEnum>
        where TEnum : SmartEnum<TEnum, TValue>
        where TValue : IEquatable<TValue>, IComparable<TValue>
    {
        /// <summary>
        ///
        /// </summary>
        /// <param name="reader"></param>
        /// <param name="typeToConvert"></param>
        /// <param name="options"></param>
        /// <returns></returns>
        /// <exception cref="JsonException"></exception>
        public override TEnum Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
        {
            switch (reader.TokenType)
            {
                case JsonTokenType.String:
                    return GetFromName(reader.GetString());

                default:
                    throw new JsonException($"Unexpected token {reader.TokenType} when parsing a smart enum.");
            }
        }

        /// <summary>
        ///
        /// </summary>
        /// <param name="writer"></param>
        /// <param name="value"></param>
        /// <param name="options"></param>
        public override void Write(Utf8JsonWriter writer, TEnum value,
            JsonSerializerOptions options)
        {
            if (value == null)
                writer.WriteNullValue();
            else
                writer.WriteStringValue(value.Name.ToString());
        }

        private TEnum GetFromName(string name)
        {
            try
            {
                return SmartEnum<TEnum, TValue>.FromName(name, false);
            }
            catch (Exception ex)
            {
                throw new JsonException($"Error converting value '{name}' to a smart enum.", ex);
            }
        }

        /// <summary>
        ///
        /// </summary>
        /// <param name="reader"></param>
        /// <param name="typeToConvert"></param>
        /// <param name="options"></param>
        /// <returns></returns>
        /// <exception cref="JsonException"></exception>
        public override TEnum ReadAsPropertyName(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
        {
            switch (reader.TokenType)
            {
                case JsonTokenType.PropertyName:
                    return GetFromName(reader.GetString());

                default:
                    throw new JsonException($"Unexpected token {reader.TokenType} when parsing a dictionary with smart enum key.");
            }
        }

        /// <summary>
        ///
        /// </summary>
        /// <param name="writer"></param>
        /// <param name="value"></param>
        /// <param name="options"></param>
        public override void WriteAsPropertyName(Utf8JsonWriter writer, TEnum value, JsonSerializerOptions options)
        {
            writer.WritePropertyName(value.Name);
        }
    }
}