是否可以指定为的DateTimeOffset的JSON.NET反序列化偏移？ [英] Is it possible to specify an offset for JSON.NET deserialization of DateTimeOffset?

问题描述

下面的语句打印1/1/0001下午4点00分〇〇秒-05：00

The following statement prints "1/1/0001 4:00:00 PM -05:00"

Console.WriteLine(JsonConvert.DeserializeObject<DateTimeOffset>("\"0001-01-01T16:00:00\""));

这是因为当json.net反序列化一个DateTime字符串（没有偏移量）来一个的DateTimeOffset对象，它赋予地方偏移，在这种情况下是-05：00

This is because when json.net deserializes a DateTime string (which doesn't have an offset) to a DateTimeOffset object, it assigns the local offset, which in this case is -05:00.

如果我不想使用本地偏移？有没有什么办法可以指定偏移量用于该反序列化？

What if I don't want to use the local offset? Is there any way I can specify an offset to use for this deserialization?

（用例是数据库服务器和Web服务器处于不同的时区，我需要有区域的不确定的时间让数据库服务器的传入的请求。反序列化抵销后）

(The use case is the database server and the web server are in different time zones, and I need the incoming requests that have zone-unspecified time to have the database server's offset after deserialization.)

更新：我无法控制传入时间字符串的格式。我有具有的DateTimeOffset属性的数据传输对象类，我需要进入的时间将数据存储到这个属性。

Update: I can't control the incoming time string's format. I have a data transfer object class which has a DateTimeOffset property and I need to store the incoming time data to this property.

推荐答案

您要反序列化到应与你所期望的数据类型。如果你不希望被列入偏移，那么就无法反序列化到一个的DateTimeOffset 。相反，反序列化到的DateTime 。这将有 DateTimeKind.Unspecified 其 .Kind 属性。

The type you're deserializing into should match the data you are expecting. If you're not expecting an offset to be included, then don't deserialize into a DateTimeOffset. Instead, deserialize to a DateTime. It will have DateTimeKind.Unspecified for its .Kind property.

您对网络服务器的时区的知识是无关的反序列化的任务。所以单独应用它，后 - 事实。

The knowledge you have about the web server's time zone is extraneous to the task of deserialization. So apply it separately, after-the-fact.

// deserialize the json
DateTime dt = JsonConvert.DeserializeObject<DateTime>("\"2014-01-01T00:00:00\"");

// find your target time zone
TimeZoneInfo tz = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time");

// apply the time zone to determine the offset, and create the DateTimeOffset
DateTimeOffset dto = new DateTimeOffset(dt, tz.GetUtcOffset(dt));

更新

每个意见，如果你需要做你所要求的方式这种转换，你需要一个自定义的JSON转换器。这应该做的伎俩：

Per comments, if you need to do this conversion in the manner you've requested, you'll need a custom json converter. This should do the trick:

public class CustomDateTimeConverter : IsoDateTimeConverter
{
    private readonly string defaultTimeZoneId;

    public CustomDateTimeConverter(string defaultTimeZoneId)
    {
        this.defaultTimeZoneId = defaultTimeZoneId;
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        if (objectType != typeof (DateTimeOffset) && objectType != typeof (DateTimeOffset?))
            return base.ReadJson(reader, objectType, existingValue, serializer);

        var dateText = reader.Value.ToString();
        if (objectType == typeof(DateTimeOffset?) && string.IsNullOrEmpty(dateText))
            return null;

        if (dateText.IndexOfAny(new[] { 'Z', 'z', '+'}) == -1 && dateText.Count(c => c == '-') == 2)
        {
            var dt = DateTime.Parse(dateText);
            var tz = TimeZoneInfo.FindSystemTimeZoneById(this.defaultTimeZoneId);
            var offset = tz.GetUtcOffset(dt);
            return new DateTimeOffset(dt, offset);
        }

        return DateTimeOffset.Parse(dateText);
    }
}

然后就可以在转换过程中连线起来：

Then you can wire it up during conversion:

var settings = new JsonSerializerSettings();
settings.DateParseHandling = DateParseHandling.None;
settings.Converters.Add(new CustomDateTimeConverter(defaultTimeZoneId: "Eastern Standard Time"));
DateTimeOffset dto = JsonConvert.DeserializeObject<DateTimeOffset>("\"2014-01-01T00:00:00\"", settings);

请务必使用一个有效的时区ID。不要使用固定的偏移量。

Be sure to used a valid time zone id. Do not use a fixed offset.

此外，这也不会，如果你想通过时间不注日期是正确的做法。这是一个完全不同的问题，并在 0001-01-01 传递的日期是不是一个伟大的方法。我会很乐意在聊天您讨论。

Also, this will not be the correct approach if you are trying to pass a time without a date. That is a completely different problem, and passing in 0001-01-01 for the date is not a great approach. I'll be happy to discuss with you in chat.

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