以特定格式将DateTime序列化为XML。

时间:2016-08-03 07:58:50

标签: c# .net xml serialization format

我有大量自动生成的类,使用.NET XmlSerializer从XML序列化/反序列化。其中一些类包含DateTime属性。

我需要使用特定格式序列化所有 DateTime属性,例如“u”。 :

System.DateTime.Now.ToString("u");
//returns something like "2008-06-15 21:15:07Z"

Deserialize方法似乎适用于这种格式,但序列化没有 - 它只是给我硬编码格式与我在托管系统中默认的相同格式(也许我可以通过更改线程设置欺骗序列化器?) (检查更新#1)。

注意: 我已经检查过几个相关问题,通过修改原始属性和添加新属性来解决它们。对我来说,由于我必须进行大量的修改,这是不可接受的。

以下是我用来测试此问题的示例测试类。

using System;
using System.Linq;
using System.Text;
using System.Xml;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using System.Xml.Linq;
using System.Xml.Serialization;
using System.Globalization;
using System.IO;

namespace FunkyTests
{
    [TestClass]
    public class SerializationTests
    {
        [TestMethod]
        public void FunkySerializationTest()
        {
            var date = DateTime.Now;
            var dummy = new Dummy() { DummyProperty = date };
            var xml = SerializeToXml(dummy);//serializes with "o" format

            var expected = date.ToString("u", new CultureInfo("en-US"));//in this example I want "u" format
            var actual = XDocument.Parse(xml).Descendants("DummyProperty").Single().Value;
            Assert.AreEqual(expected, actual);
        }

        [TestMethod]
        public void FunkyDeserializationTest()
        {
            var date = DateTime.Now;
            var dummy = new Dummy() { DummyProperty = date };
            var xml = SerializeToXml(dummy);//serializes with "o" format
            var deserializedDummy = DeserializeFromXml<Dummy>(xml);

            Assert.AreEqual(dummy.DummyProperty, deserializedDummy.DummyProperty);
        }

        private static T DeserializeFromXml<T>(string xml)
        {
            using (var textReader = new StringReader(xml))
            {
                using (var reader = XmlReader.Create(textReader))
                {
                    var serializer = new XmlSerializer(typeof(T));
                    var result = serializer.Deserialize(reader);
                    return (T)result;
                }
            }
        }

        private static string SerializeToXml<T>(T objectToSerialize)
        {
            var xml = new StringBuilder();
            using (var writer = XmlWriter.Create(xml, new XmlWriterSettings { OmitXmlDeclaration = true }))
            {
                var ns = new XmlSerializerNamespaces();
                ns.Add(string.Empty, string.Empty);

                var serializer = new XmlSerializer(typeof(T));
                serializer.Serialize(writer, objectToSerialize, ns);
            }
            return xml.ToString();
        }

        public class Dummy
        {
            public DateTime DummyProperty { get; set; }
        }
    }
}

任何时髦的想法?

更新#1: 我认为日期序列化依赖于Thread.CurrentCulture。如果我正确解释XmlSerializer代码,格式是硬编码的(谢谢ILSpy)。

// System.Xml.Serialization.XmlCustomFormatter
internal static string FromDateTime(DateTime value)
{
    if (XmlCustomFormatter.Mode == DateTimeSerializationSection.DateTimeSerializationMode.Local)
    {
        return XmlConvert.ToString(value, "yyyy-MM-ddTHH:mm:ss.fffffffzzzzzz");
    }
    return XmlConvert.ToString(value, XmlDateTimeSerializationMode.RoundtripKind);
}

更新#2:我添加了一个测试方法,该方法使用Alexander Petrov提出的答案。它没有断言Ticks。根据{{​​3}}问题是在DateTime的内部,并且是由于丢失了DateTime的“Kind”。建议使用DateTimeOffset,这导致了另一个序列化问题,在Serialize DateTime as binary中解释

1 个答案:

答案 0 :(得分:1)

尝试使用自定义xml阅读器和编写器。

public class CustomDateTimeWriter : XmlTextWriter
{
    public CustomDateTimeWriter(TextWriter writer) : base(writer) { }
    public CustomDateTimeWriter(Stream stream, Encoding encoding) : base(stream, encoding) { }
    public CustomDateTimeWriter(string filename, Encoding encoding) : base(filename, encoding) { }

    public override void WriteRaw(string data)
    {
        DateTime dt;

        if (DateTime.TryParse(data, out dt))
            base.WriteRaw(dt.ToString("u", new CultureInfo("en-US")));
        else
            base.WriteRaw(data);
    }
}

public class CustomDateTimeReader : XmlTextReader
{
    public CustomDateTimeReader(TextReader input) : base(input) { }
    // define other required constructors

    public override string ReadElementString()
    {
        string data = base.ReadElementString();
        DateTime dt;

        if (DateTime.TryParse(data, null, DateTimeStyles.AdjustToUniversal, out dt))
            return dt.ToString("o");
        else
            return data;
    }
}

使用

var dummy = new Dummy { DummyProperty = DateTime.Now };
Console.WriteLine(dummy.DummyProperty);
var xs = new XmlSerializer(typeof(Dummy));
string xml;

using (var stringWriter = new StringWriter())
using (var xmlWriter = new CustomDateTimeWriter(stringWriter))
{
    xmlWriter.Formatting = Formatting.Indented;

    xs.Serialize(xmlWriter, dummy);
    xml = stringWriter.ToString();
}

Console.WriteLine(xml);

using (var stringReader = new StringReader(xml))
using (var xmlReader = new CustomDateTimeReader(stringReader))
{
    dummy = (Dummy)xs.Deserialize(xmlReader);
    Console.WriteLine(dummy.DummyProperty);
}

<强>优点:

此方法自动(de)将所有日期时间值序列化为所需格式,而无需更改生成的类。

<强>缺点:

此方法可能会意外更改日期时间等值。

这种方法可能会减慢(反)序列化的速度。