blocks|key|245948|text|你在正确的轨道上。既然您说不能修改全局设置，那么下一个最好的方法就是按照您的建议，根据需要应用JsonConverter属性。事实证明，Json.Net已经有一个内置的IsoDateTimeConverter，可以让您指定日期格式。不幸的是，您不能通过JsonConverter属性设置格式，因为该属性的惟一参数是一个类型。但是，有一个简单的解决方案:将IsoDateTimeConverter子类化，然后在子类的构造函数中指定日期格式。在需要的地方应用JsonConverter属性，指定您的自定义转换器，您就可以开始工作了。下面是所需的全部代码：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|245949|class+CustomDateTimeConverter+:+IsoDateTimeConverter
{
++++public+CustomDateTimeConverter()
++++{
++++++++base.DateTimeFormat+=+"yyyy-MM-dd";
++++}
}|code-block|syntax|javascript|245950|如果你不介意有时间在那里，你甚至不需要子类化IsoDateTimeConverter。它的默认日期格式是yyyy'-'MM'-'dd'T'HH':'mm':'ss.FFFFFFFK+(如source+code中所示)。|245951|entityMap|0|LINK|mutability|MUTABLE|url|http://james.newtonking.com/projects/json/help/?topic=html/T_Newtonsoft_Json_Converters_IsoDateTimeConverter.htm|1|https://github.com/JamesNK/Newtonsoft.Json/blob/master/Src/Newtonsoft.Json/Converters/IsoDateTimeConverter.cs^0|1B|D|2C|K|3I|D|4X|K|6B|D|2C|K|0|0|0|1G|12|2L|B|1|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]|$9|11|A|12|B|C]|$9|13|A|14|B|C]|$9|15|A|16|B|C]]|D|@$9|17|A|18|1|19]]|E|$]]|$1|F|3|G|5|H|7|1A|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|1B|8|@$9|1C|A|1D|B|C]]|D|@$9|1E|A|1F|1|1G]]|E|$]]|$1|M|3|-4|5|6|7|1H|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]|U|$5|P|Q|R|E|$S|V]]]]

You are on the right track. Since you said you can't modify the global settings, then the next best thing is to apply the <code>JsonConverter</code> attribute on an as-needed basis, as you suggested. It turns out Json.Net already has a built-in <a href="http://james.newtonking.com/projects/json/help/?topic=html/T_Newtonsoft_Json_Converters_IsoDateTimeConverter.htm" rel="noreferrer"><code>IsoDateTimeConverter</code></a> that lets you specify the date format. Unfortunately, you can't set the format via the <code>JsonConverter</code> attribute, since the attribute's sole argument is a type. However, there is a simple solution: subclass the <code>IsoDateTimeConverter</code>, then specify the date format in the constructor of the subclass. Apply the <code>JsonConverter</code> attribute where needed, specifying your custom converter, and you're ready to go. Here is the entirety of the code needed:

<pre><code>class CustomDateTimeConverter : IsoDateTimeConverter
{
 public CustomDateTimeConverter()
 {
 base.DateTimeFormat = "yyyy-MM-dd";
 }
}
</code></pre>

If you don't mind having the time in there also, you don't even need to subclass the IsoDateTimeConverter. Its default date format is <code>yyyy'-'MM'-'dd'T'HH':'mm':'ss.FFFFFFFK</code> (as seen in the <a href="https://github.com/JamesNK/Newtonsoft.Json/blob/master/Src/Newtonsoft.Json/Converters/IsoDateTimeConverter.cs" rel="noreferrer">source code</a>).

blocks|key|29788|text|也可以使用IsoDateTimeConverter实例完成此操作，而无需更改全局格式设置：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|29789|string+json+=+JsonConvert.SerializeObject(yourObject,
++++new+IsoDateTimeConverter()+{+DateTimeFormat+=+"yyyy-MM-dd+HH:mm:ss"+});|code-block|syntax|javascript|29790|它使用接受params+JsonConverter[]参数的JsonConvert.SerializeObject重载。|29791|entityMap^0|5|K|0|0|5|M|U|R|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|N|$]]

It can also be done with an <code>IsoDateTimeConverter</code> instance, without changing global formatting settings:

<pre><code>string json = JsonConvert.SerializeObject(yourObject,
 new IsoDateTimeConverter() { DateTimeFormat = "yyyy-MM-dd HH:mm:ss" });
</code></pre>

This uses the <code>JsonConvert.SerializeObject</code> overload that takes a <code>params JsonConverter[]</code> argument.

blocks|key|29817|text|也可以使用其中一个序列化程序设置重载：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|29818|var+json+=+JsonConvert.SerializeObject(someObject,+new+JsonSerializerSettings()+{+DateFormatString+=+"yyyy-MM-ddThh:mm:ssZ"+});|code-block|syntax|javascript|29819|或|29820|var+json+=+JsonConvert.SerializeObject(someObject,+Formatting.Indented,+new+JsonSerializerSettings()+{+DateFormatString+=+"yyyy-MM-ddThh:mm:ssZ"+});|29821|带类型的重载也是可用的。|29822|entityMap^0|0|0|0|0|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]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Also available using one of the serializer settings overloads:

<pre><code>var json = JsonConvert.SerializeObject(someObject, new JsonSerializerSettings() { DateFormatString = "yyyy-MM-ddThh:mm:ssZ" });
</code></pre>

Or

<pre><code>var json = JsonConvert.SerializeObject(someObject, Formatting.Indented, new JsonSerializerSettings() { DateFormatString = "yyyy-MM-ddThh:mm:ssZ" });
</code></pre>

Overloads taking a Type are also available.

blocks|key|29844|text|您可以使用此方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|29845|public+class+DateFormatConverter+:+IsoDateTimeConverter
{
++++public+DateFormatConverter(string+format)
++++{
++++++++DateTimeFormat+=+format;
++++}
}|code-block|syntax|javascript|29846|并这样使用它：|29847|class+ReturnObjectA+
{
++++[JsonConverter(typeof(DateFormatConverter),+"yyyy-MM-dd")]
++++public+DateTime+ReturnDate+{+get;set;}
}|29848|DateTimeFormat字符串使用此处描述的.NET格式字符串语法：https://docs.microsoft.com/en-us/dotnet/standard/base-types/custom-date-and-time-format-strings|offset|length|style|CODE|29849|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.microsoft.com/en-us/dotnet/standard/base-types/custom-date-and-time-format-strings^0|0|0|0|0|0|E|10|2N|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|10|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|12|8|@$M|13|N|14|O|P]]|9|@$M|15|N|16|1|17]]|A|$]]|$1|Q|3|-4|5|6|7|18|8|@]|9|@]|A|$]]]|R|$S|$5|T|U|V|A|$W|X]]]]

You could use this approach:
<pre><code>public class DateFormatConverter : IsoDateTimeConverter
{
 public DateFormatConverter(string format)
 {
 DateTimeFormat = format;
 }
}
</code></pre>
And use it this way:
<pre><code>class ReturnObjectA 
{
 [JsonConverter(typeof(DateFormatConverter), &quot;yyyy-MM-dd&quot;)]
 public DateTime ReturnDate { get;set;}
}
</code></pre>
The <code>DateTimeFormat</code> string uses the .NET format string syntax described here: <a href="https://docs.microsoft.com/en-us/dotnet/standard/base-types/custom-date-and-time-format-strings" rel="nofollow noreferrer">https://docs.microsoft.com/en-us/dotnet/standard/base-types/custom-date-and-time-format-strings</a>

blocks|key|29875|text|还有另一个我一直在使用的解决方案。只需创建一个字符串属性并将其用于json即可。此属性将返回格式正确的日期。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|29876|class+JSonModel+{
++++...

++++[JsonIgnore]
++++public+DateTime+MyDate+{+get;+set;+}

++++[JsonProperty("date")]
++++public+string+CustomDate+{
++++++++get+{+return+MyDate.ToString("ddMMyyyy");+}
++++++++//+set+{+MyDate+=+DateTime.Parse(value);+}
++++++++set+{+MyDate+=+DateTime.ParseExact(value,+"ddMMyyyy",+null);+}
++++}

++++...
}|code-block|syntax|javascript|29877|这样你就不必创建额外的类了。此外，它还允许您创建不同的数据格式。例如，您可以使用相同的DateTime轻松地为小时创建另一个属性。|29878|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

There is another solution I've been using. Just create a string property and use it for json. This property wil return date properly formatted.
<pre><code>class JSonModel {
 ...

 [JsonIgnore]
 public DateTime MyDate { get; set; }

 [JsonProperty(&quot;date&quot;)]
 public string CustomDate {
 get { return MyDate.ToString(&quot;ddMMyyyy&quot;); }
 // set { MyDate = DateTime.Parse(value); }
 set { MyDate = DateTime.ParseExact(value, &quot;ddMMyyyy&quot;, null); }
 }

 ...
}
</code></pre>
This way you don't have to create extra classes. Also, it allows you to create diferent data formats. e.g, you can easily create another Property for Hour using the same DateTime.

blocks|key|29924|text|使用下面的转换器|type|unstyled|depth|inlineStyleRanges|entityRanges|data|29925|public+class+CustomDateTimeConverter+:+IsoDateTimeConverter
++++{
++++++++public+CustomDateTimeConverter()
++++++++{
++++++++++++DateTimeFormat+=+"yyyy-MM-dd";
++++++++}

++++++++public+CustomDateTimeConverter(string+format)
++++++++{
++++++++++++DateTimeFormat+=+format;
++++++++}
++++}|code-block|syntax|javascript|29926|可以在默认的自定义格式中使用它|29927|class+ReturnObjectA+
{
++++[JsonConverter(typeof(CustomDateTimeConverter))]
++++public+DateTime+ReturnDate+{+get;set;}
}|29928|或属性的任何指定格式。|29929|class+ReturnObjectB+
{
++++[JsonConverter(typeof(CustomDateTimeConverter),+"dd+MMM+yy")]
++++public+DateTime+ReturnDate+{+get;set;}
}|29930|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

With below converter
<pre><code>public class CustomDateTimeConverter : IsoDateTimeConverter
 {
 public CustomDateTimeConverter()
 {
 DateTimeFormat = &quot;yyyy-MM-dd&quot;;
 }

 public CustomDateTimeConverter(string format)
 {
 DateTimeFormat = format;
 }
 }
</code></pre>
Can use it with a default custom format
<pre><code>class ReturnObjectA 
{
 [JsonConverter(typeof(CustomDateTimeConverter))]
 public DateTime ReturnDate { get;set;}
}
</code></pre>
Or any specified format for a property
<pre><code>class ReturnObjectB 
{
 [JsonConverter(typeof(CustomDateTimeConverter), &quot;dd MMM yy&quot;)]
 public DateTime ReturnDate { get;set;}
}
</code></pre>

blocks|key|246156|text|public+static+JsonSerializerSettings+JsonSerializer+{+get;+set;+}+=+new+JsonSerializerSettings()
++++++++{
++++++++++++DateFormatString=+"yyyy-MM-dd+HH:mm:ss",
++++++++++++NullValueHandling+=+NullValueHandling.Ignore,
++++++++++++ContractResolver+=+new+LowercaseContractResolver()
++++++++};|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|246157|你好,|unstyled|246158|当我需要设置JsonSerializerSettings时，我将使用此属性|246159|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|L|8|@]|9|@]|A|$]]|$1|G|3|H|5|F|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|F|7|N|8|@]|9|@]|A|$]]]|J|$]]

<pre><code>public static JsonSerializerSettings JsonSerializer { get; set; } = new JsonSerializerSettings()
 {
 DateFormatString= &quot;yyyy-MM-dd HH:mm:ss&quot;,
 NullValueHandling = NullValueHandling.Ignore,
 ContractResolver = new LowercaseContractResolver()
 };
</code></pre>
Hello,
I'm using this property when I need set JsonSerializerSettings

I am developing an API to expose some data using ASP.NET Web API.

In one of the API, the client wants us to expose the date in <code>yyyy-MM-dd</code> format. I don't want to change the global settings (e.g. <code>GlobalConfiguration.Configuration.Formatters.JsonFormatter</code>) for that since it is very specific to this client. And I do developing that in a solution for multiple clients.

One of the solution that I could think of is to create a custom <code>JsonConverter</code> and then put that to the property I need to do the custom formatting

e.g.

<pre><code>class ReturnObjectA 
{
 [JsonConverter(typeof(CustomDateTimeConverter))]
 public DateTime ReturnDate { get;set;}
}
</code></pre>

Just wondering if there is some other easy way of doing that.

Specifying a custom DateTime format when serializing with Json.Net

我正在开发一个应用程序接口，以使用ASP.NET Web API公开一些数据。在其中一个应用程序接口中，客户端希望我们以yyyy-MM-dd格式公开日期。我不想为此更改全局设置(例如GlobalConfiguration.Configuration.Formatters.JsonFormatter)，因为它非常特定于此...

问在使用Json.Net进行序列化时指定自定义DateTime格式
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