blocks|key|293043|text|如果您的时区为GMT%2B1，则您所在时区的DateTime.MinValue的UTC值将比DateTime.MinValue小一个小时。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|293044|entityMap^0|K|H|18|H|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

If your time zone is GMT+1, then the UTC value of <code>DateTime.MinValue</code> in your time zone is going to be an hour less than <code>DateTime.MinValue</code>.

blocks|key|3014621|text|主要的问题是DateTime.MinValue有DateTimeKind.Unspecified类型。它被定义为：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3014622|MinValue+=+new+DateTime(0L,+DateTimeKind.Unspecified);|code-block|syntax|javascript|3014623|但这并不是一个真正的问题，这个定义会在序列化过程中导致问题。JSON+DateTime序列化通过以下方式完成：|3014624|System.Runtime.Serialization.Json.JsonWriterDelegator.WriteDateTime(DateTime+value)|3014625|不幸的是，它被定义为：|3014626|...

if+(value.Kind+!=+DateTimeKind.Utc)
{
++++long+num+=+value.Ticks+-+TimeZone.CurrentTimeZone.GetUtcOffset(value).Ticks;
++++if+((num+>+DateTime.MaxValue.Ticks)+%7C%7C+(num+<+DateTime.MinValue.Ticks))
++++{
++++++++throw+DiagnosticUtility.ExceptionUtility.ThrowHelperError(XmlObjectSerializer.CreateSerializationException(SR.GetString("JsonDateTimeOutOfRange"),+new+ArgumentOutOfRangeException("value")));
++++}
}

...|3014627|因此，它不考虑Unspecified，并将其视为Local。为了避免这种情况，您可以定义自己的常量：|3014628|MinValueUtc+=+new+DateTime(0L,+DateTimeKind.Utc);|3014629|或|3014630|MinValueUtc+=+DateTime.MinValue.ToUniversalTime();|3014631|当然，这看起来很奇怪，但它很有帮助。|3014632|entityMap^0|6|H|O|O|0|0|0|0|0|0|7|B|O|5|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@$9|15|A|16|B|C]|$9|17|A|18|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|19|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|1A|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|1B|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|1C|8|@]|D|@]|E|$]]|$1|Q|3|R|5|H|7|1D|8|@]|D|@]|E|$I|J]]|$1|S|3|T|5|6|7|1E|8|@$9|1F|A|1G|B|C]|$9|1H|A|1I|B|C]]|D|@]|E|$]]|$1|U|3|V|5|H|7|1J|8|@]|D|@]|E|$I|J]]|$1|W|3|X|5|6|7|1K|8|@]|D|@]|E|$]]|$1|Y|3|Z|5|H|7|1L|8|@]|D|@]|E|$I|J]]|$1|10|3|11|5|6|7|1M|8|@]|D|@]|E|$]]|$1|12|3|-4|5|6|7|1N|8|@]|D|@]|E|$]]]|13|$]]

The main problem is <code>DateTime.MinValue</code> has <code>DateTimeKind.Unspecified</code> kind. It is defined as:

<pre class="lang-cs prettyprint-override"><code>MinValue = new DateTime(0L, DateTimeKind.Unspecified);
</code></pre>

But this is not a real problem, this definition leads to problem during serialization. JSON DateTime serialization done through:

<pre class="lang-cs prettyprint-override"><code>System.Runtime.Serialization.Json.JsonWriterDelegator.WriteDateTime(DateTime value)
</code></pre>

Unfortunately it is defined as:

<pre class="lang-cs prettyprint-override"><code>...

if (value.Kind != DateTimeKind.Utc)
{
 long num = value.Ticks - TimeZone.CurrentTimeZone.GetUtcOffset(value).Ticks;
 if ((num &gt; DateTime.MaxValue.Ticks) || (num &lt; DateTime.MinValue.Ticks))
 {
 throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(XmlObjectSerializer.CreateSerializationException(SR.GetString("JsonDateTimeOutOfRange"), new ArgumentOutOfRangeException("value")));
 }
}

...
</code></pre>

So it doesn't take into account <code>Unspecified</code> and treats it as <code>Local</code>. To avoid this situation you can define your own constant:

<pre class="lang-cs prettyprint-override"><code>MinValueUtc = new DateTime(0L, DateTimeKind.Utc);
</code></pre>

or 

<pre class="lang-cs prettyprint-override"><code>MinValueUtc = DateTime.MinValue.ToUniversalTime();
</code></pre>

It looks weird of course, but it helps.

blocks|key|293811|text|使用此构造函数：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|293812|public+DataContractJsonSerializer(Type+type,+IEnumerable<Type>+knownTypes,+int+maxItemsInObjectGraph,+bool+ignoreExtensionDataObject,+IDataContractSurrogate+dataContractSurrogate,+bool+alwaysEmitTypeInformation)|code-block|syntax|javascript|293813|示例代码：|293814|DataContractJsonSerializer+serializer+=+new+DataContractJsonSerializer(o.GetType(),+null,+int.MaxValue,+false,+new+DateTimeSurrogate(),+false);

+public+class+DateTimeSurrogate+:+IDataContractSurrogate
++++{

++++++++#region+IDataContractSurrogate+成员

++++++++public+object+GetCustomDataToExport(Type+clrType,+Type+dataContractType)
++++++++{
++++++++++++return+null;
++++++++}

++++++++public+object+GetCustomDataToExport(System.Reflection.MemberInfo+memberInfo,+Type+dataContractType)
++++++++{
++++++++++++return+null;
++++++++}

++++++++public+Type+GetDataContractType(Type+type)
++++++++{
++++++++++++return+type;
++++++++}

++++++++public+object+GetDeserializedObject(object+obj,+Type+targetType)
++++++++{
+++++++++++++++++++return+obj;
++++++++}

++++++++public+void+GetKnownCustomDataTypes(System.Collections.ObjectModel.Collection<Type>+customDataTypes)
++++++++{

++++++++}

++++++++public+object+GetObjectToSerialize(object+obj,+Type+targetType)
++++++++{
++++++++++++if+(obj.GetType()+==+typeof(DateTime))
++++++++++++{
++++++++++++++++DateTime+dt+=+(DateTime)obj;
++++++++++++++++if+(dt+==+DateTime.MinValue)
++++++++++++++++{
++++++++++++++++++++dt+=+DateTime.MinValue.ToUniversalTime();
++++++++++++++++++++return+dt;
++++++++++++++++}
++++++++++++++++return+dt;
++++++++++++}
++++++++++++if+(obj+==+null)
++++++++++++{
++++++++++++++++return+null;
++++++++++++}
++++++++++++var+q+=+from+p+in+obj.GetType().GetProperties()
++++++++++++++++++++where+(p.PropertyType+==+typeof(DateTime))+&&+(DateTime)p.GetValue(obj,+null)+==+DateTime.MinValue
++++++++++++++++++++select+p;
++++++++++++q.ToList().ForEach(p+=>
++++++++++++{
++++++++++++++++p.SetValue(obj,+DateTime.MinValue.ToUniversalTime(),+null);
++++++++++++});
++++++++++++return+obj;
++++++++}

++++++++public+Type+GetReferencedTypeOnImport(string+typeName,+string+typeNamespace,+object+customData)
++++++++{
++++++++++++return+null;
++++++++}

++++++++public+System.CodeDom.CodeTypeDeclaration+ProcessImportedType(System.CodeDom.CodeTypeDeclaration+typeDeclaration,+System.CodeDom.CodeCompileUnit+compileUnit)
++++++++{
++++++++++++return+typeDeclaration;
++++++++}

++++++++#endregion
++++}|293815|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

using this constructor:

<pre><code>public DataContractJsonSerializer(Type type, IEnumerable&lt;Type&gt; knownTypes, int maxItemsInObjectGraph, bool ignoreExtensionDataObject, IDataContractSurrogate dataContractSurrogate, bool alwaysEmitTypeInformation)
</code></pre>

example code:

<pre><code>DataContractJsonSerializer serializer = new DataContractJsonSerializer(o.GetType(), null, int.MaxValue, false, new DateTimeSurrogate(), false);

 public class DateTimeSurrogate : IDataContractSurrogate
 {

 #region IDataContractSurrogate 成员

 public object GetCustomDataToExport(Type clrType, Type dataContractType)
 {
 return null;
 }

 public object GetCustomDataToExport(System.Reflection.MemberInfo memberInfo, Type dataContractType)
 {
 return null;
 }

 public Type GetDataContractType(Type type)
 {
 return type;
 }

 public object GetDeserializedObject(object obj, Type targetType)
 {
 return obj;
 }

 public void GetKnownCustomDataTypes(System.Collections.ObjectModel.Collection&lt;Type&gt; customDataTypes)
 {

 }

 public object GetObjectToSerialize(object obj, Type targetType)
 {
 if (obj.GetType() == typeof(DateTime))
 {
 DateTime dt = (DateTime)obj;
 if (dt == DateTime.MinValue)
 {
 dt = DateTime.MinValue.ToUniversalTime();
 return dt;
 }
 return dt;
 }
 if (obj == null)
 {
 return null;
 }
 var q = from p in obj.GetType().GetProperties()
 where (p.PropertyType == typeof(DateTime)) &amp;&amp; (DateTime)p.GetValue(obj, null) == DateTime.MinValue
 select p;
 q.ToList().ForEach(p =&gt;
 {
 p.SetValue(obj, DateTime.MinValue.ToUniversalTime(), null);
 });
 return obj;
 }

 public Type GetReferencedTypeOnImport(string typeName, string typeNamespace, object customData)
 {
 return null;
 }

 public System.CodeDom.CodeTypeDeclaration ProcessImportedType(System.CodeDom.CodeTypeDeclaration typeDeclaration, System.CodeDom.CodeCompileUnit compileUnit)
 {
 return typeDeclaration;
 }

 #endregion
 }
</code></pre>

blocks|key|3228814|text|尝试在任何DateTime成员上添加此内容|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3228815|[DataMember(IsRequired+=+false,+EmitDefaultValue+=+false)]|code-block|syntax|javascript|3228816|大多数这些错误的发生是因为datetime的默认值是DateTime.MinValue，它来自年份1，而JSON序列化是来自1970年。|offset|length|style|CODE|3228817|entityMap^0|0|0|D|8|Q|H|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|N|$]]

Try to add this on any DateTime Member

<pre><code>[DataMember(IsRequired = false, EmitDefaultValue = false)]
</code></pre>

Most of these erros happens because the default value of the <code>datetime</code> is <code>DateTime.MinValue</code> which is from year of 1 and the JSON serialization is from year 1970.

blocks|key|290828|text|您可以在序列化期间通过OnSerializing属性和一些反射来修复该问题：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|290829|[OnSerializing]
public+void+OnSerializing(StreamingContext+context)
{
++var+properties+=+this.GetType().GetProperties();
++foreach+(PropertyInfo+property+in+properties)
++{
++++if+(property.PropertyType+==+typeof(DateTime)+&&+property.GetValue(this).Equals(DateTime.MinValue))
++++{
++++++property.SetValue(this,+DateTime.MinValue.ToUniversalTime());
++++}
++}
}|code-block|syntax|javascript|290830|entityMap|0|LINK|mutability|MUTABLE|url|https://msdn.microsoft.com/en-us/library/x4wddfsb^0|B|D|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

You could fix that during serialization via the <a href="https://msdn.microsoft.com/en-us/library/x4wddfsb" rel="nofollow">OnSerializing</a> attribute and some reflection:

<pre><code>[OnSerializing]
public void OnSerializing(StreamingContext context)
{
 var properties = this.GetType().GetProperties();
 foreach (PropertyInfo property in properties)
 {
 if (property.PropertyType == typeof(DateTime) &amp;&amp; property.GetValue(this).Equals(DateTime.MinValue))
 {
 property.SetValue(this, DateTime.MinValue.ToUniversalTime());
 }
 }
}
</code></pre>

blocks|key|3014717|text|我认为一种更优雅的方法是指示序列化程序不发出DateTime字段的默认值。这将在传输过程中节省一些字节，并在序列化没有任何值的字段时进行一些处理。示例：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3014718|[DataContract]
public+class+Document+{
++++[DataMember]+
++++public+string+Title+{+get;+set;+}
++++[DataMember(IsRequired+=+false,+EmitDefaultValue+=+false)]+
++++public+DateTime+Modified+{+get;+set;+}+
}|code-block|syntax|javascript|3014719|或者，您可以使用Nullable。示例：|3014720|[DataContract]
public+class+Document+{
++++[DataMember]+
++++public+string+Title+{+get;+set;+}
++++[DataMember]+
++++public+DateTime?+Modified+{+get;+set;+}+
}|3014721|这完全取决于您的项目中可能存在的要求和限制。有时，您不能只更改数据类型。在这种情况下，您仍然可以利用DataMember属性并保持数据类型不变。|offset|length|style|CODE|3014722|在上面的示例中，如果您在服务器端使用了new+Document()+{+Title+=+"Test+Document"+}，那么当序列化到JSON时，它将提供{"Title":+"Test+Document"}，因此在JavaScript中或在线路另一端的任何其他客户端中将更容易处理。在JavaScript中，如果你JSON.Parse()它，并尝试读取它，你会得到undefined。在类型化语言中，该属性的默认值取决于类型(这通常是预期的行为)。|3014723|library.GetDocument(id).success(function(raw){+
++++var+document+=+JSON.Parse(raw);
++++var+date+=+document.date;+//+date+will+be+*undefined*
++++...
}|3014724|entityMap^0|0|0|0|0|1E|A|0|J|16|27|Q|54|9|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|10|8|@$M|11|N|12|O|P]]|9|@]|A|$]]|$1|Q|3|R|5|6|7|13|8|@$M|14|N|15|O|P]|$M|16|N|17|O|P]|$M|18|N|19|O|P]]|9|@]|A|$]]|$1|S|3|T|5|D|7|1A|8|@]|9|@]|A|$E|F]]|$1|U|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]]|V|$]]

I believe a more elegant way is to instruct the serializer not to emit the default value for DateTime fields. This will save some byte during transfer and some processing when serializing for the fields that you don't have any value for them.
Example:

<pre><code>[DataContract]
public class Document {
 [DataMember] 
 public string Title { get; set; }
 [DataMember(IsRequired = false, EmitDefaultValue = false)] 
 public DateTime Modified { get; set; } 
}
</code></pre>

or you can use Nullables. Example:

<pre><code>[DataContract]
public class Document {
 [DataMember] 
 public string Title { get; set; }
 [DataMember] 
 public DateTime? Modified { get; set; } 
}
</code></pre>

It all depends on the requirements and restrictions you might have in your project. Sometimes you cannot just change the data types. In that case you can still take advantage of <code>DataMember</code> attribute and keep the data types intact.

In the above example if you have <code>new Document() { Title = "Test Document" }</code> in the server side, when serialized to JSON it will give you <code>{"Title": "Test Document"}</code> so it will be easier to deal with in JavaScript or any other client in the other side of the wire. In JavaScript if you JSON.Parse() it, and try to read it, you will get back <code>undefined</code>. In typed languages you will have the default value for that property depending on the type (which is typically the expected behavior).

<pre><code>library.GetDocument(id).success(function(raw){ 
 var document = JSON.Parse(raw);
 var date = document.date; // date will be *undefined*
 ...
}
</code></pre>

blocks|key|295913|text|可以通过指定自定义DateTimeFormat来避免这个问题(使用WriteDateTimeInDefaultFormat方法)：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|295914|DataContractJsonSerializerSettings+settings+=+new+DataContractJsonSerializerSettings();
settings.DateTimeFormat+=+new+DateTimeFormat("yyyy-MM-ddThh:mm:ss.fffZ");
DataContractJsonSerializer+serializer+=+new+DataContractJsonSerializer(typeof(MyDataContract),+settings);|code-block|syntax|javascript|295915|请注意，您应该确保UTC的值确实是以UTC为单位的，但这对于使用DateTime.MinValue是安全的。|295916|有关正在使用的DateTimeFormat的其他详细信息，请参阅this。|offset|length|295917|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/10286204/the-right-json-date-format^0|0|0|0|W|4|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|X|8|@]|9|@$K|Y|L|Z|1|10]]|A|$]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|T]]]]

It's possible to avoid the issue (with the WriteDateTimeInDefaultFormat method) by specifying a custom DateTimeFormat:

<pre><code>DataContractJsonSerializerSettings settings = new DataContractJsonSerializerSettings();
settings.DateTimeFormat = new DateTimeFormat("yyyy-MM-ddThh:mm:ss.fffZ");
DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(MyDataContract), settings);
</code></pre>

Note that you should make sure that the DateTime value is really in UTC, but this is safe to use with DateTime.MinValue.

See <a href="https://stackoverflow.com/questions/10286204/the-right-json-date-format">this</a> for additional details about the DateTimeFormat being used.

I am experiencing issues with a WCF REST service. The wire object that I try to return has certain properties not set, resulting in DateTime.MinValue for properties of type DateTime. The service returns an empty document (with HTTP status 200 ???). When I try to call JSON serialization myself, the exception that is thrown is:

<blockquote>
 SerializationException: DateTime values that are greater than DateTime.MaxValue or smaller than DateTime.MinValue when converted to UTC cannot be serialized to JSON.
</blockquote>

This can be reproduced by running the following code in a console app:

<pre><code>DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(DateTime));
MemoryStream m = new MemoryStream();
DateTime dt = DateTime.MinValue;

// throws SerializationException in my timezone
ser.WriteObject(m, dt);
string json = Encoding.ASCII.GetString(m.GetBuffer());
Console.WriteLine(json);
</code></pre>

Why is this behaviour? I think it is related to my timezone (GMT+1). As DateTime.MinValue is default(DateTime), I would expect that this can be serialized without problems.

Any tips on how to make my REST service behave? I don't want to change my DataContract.

Why can DateTime.MinValue not be serialized in timezones ahead of UTC?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋 

腾讯云代码助手

CODING DevOps

Cloud Studio

SDK中心

API中心

命令行工具

我遇到了WCF REST服务的问题。我尝试返回的wire对象没有设置某些属性，导致DateTime类型的属性为DateTime.MinValue。该服务返回一个空文档( HTTP状态为200？)。当我自己尝试调用JSON序列化时，抛出的异常是： SerializationException:转换为DateTime时大于...

问为什么DateTime.MinValue不能在协调世界时之前按时区序列化？
EN

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问为什么DateTime.MinValue不能在协调世界时之前按时区序列化？EN