Json.Net，如何用“Z”而不是+00:00序列化DateTimeOffset，但保留其他时区偏移量？

使用 .NET Core 和 Json.NET，我如何序列化DateTimeOffset (not DateTime) 使得 UTC+00:00变成Z同时保留任何其他时区偏移量（-04:00例如）？

这个帖子 https://stackoverflow.com/a/42816827/918244 is for DateTime，但是有了它，我设法替换了+00:00 by Z转换时all时区转换为 UTC

new JsonSerializerSettings {
    Converters = new JsonConverter[] {
        new IsoDateTimeConverter {
            DateTimeStyles = DateTimeStyles.AdjustToUniversal,
            DateTimeFormat = "yyyy'-'MM'-'dd'T'HH':'mm':'ss'Z'",
        }
    }
};

我想保留时区偏移信息，i.e.

2019-12-10T17:00:00Z for new DateTimeOffset(2019, 12, 10, 17, 0, 0, TimeSpan.Zero)

and

2019-12-10T13:00:00-04:00 for new DateTimeOffset(2019, 12, 10, 13, 0, 0, TimeSpan.FromHours(-4))

The DateTimeFormat = "yyyy'-'MM'-'dd'T'HH':'mm':'ssK"建议的作品DateTime但输出+00:00, not Z, for DateTimeOffset...

See 这个 .NET Fiddle 用于复制 https://dotnetfiddle.net/iduukx我的尝试。

你可以子类化IsoDateTimeConverter https://github.com/JamesNK/Newtonsoft.Json/blob/master/Src/Newtonsoft.Json/Converters/IsoDateTimeConverter.cs并覆盖CanConvert https://www.newtonsoft.com/json/help/html/M_Newtonsoft_Json_Converters_DateTimeConverterBase_CanConvert.htm仅转换类型的对象DateTimeOffset and DateTimeOffset?。那么，当DateTimeOffset.Offset为零，输出为DateTime通用格式：

public class IsoDateTimeOffsetConverter : IsoDateTimeConverter
{
    public override bool CanConvert(Type objectType)
    {
        return objectType == typeof(DateTimeOffset) || objectType == typeof(DateTimeOffset?);
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        var dateTimeOffset = (DateTimeOffset)value;
        if (dateTimeOffset.Offset == TimeSpan.Zero)
        {
            // If there is no offset, serialize as a DateTime
            base.WriteJson(writer, dateTimeOffset.UtcDateTime, serializer);
        }
        else
        {
            base.WriteJson(writer, value, serializer);
        }
    }       
}

然后像这样使用它：

var settings = new JsonSerializerSettings {
    Converters = {
        new IsoDateTimeOffsetConverter(),
    }
};

演示小提琴here https://dotnetfiddle.net/dbsGIR.