C# web api返回范例设置为json的两种要领【C#.Net教程】,C#，api，json

web api写api接口时默许返回的是把你的对象序列化后以XML情势返回，那末怎样才能让其返回为json呢，下面就引见两种要领：
要领一：(改设置法)

找到Global.asax文件，在Application_Start()要领中增加一句：

GlobalConfiguration.Configuration.Formatters.XmlFormatter.SupportedMediaTypes.Clear();

修改后：

<br>protected void Application_Start() <br>{ <br>AreaRegistration.RegisterAllAreas();
 <br>WebApiConfig.Register(GlobalConfiguration.Configuration); 
 <br>FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters); 
 <br>RouteConfig.RegisterRoutes(RouteTable.Routes); 
 <br>// 使api返回为jsonGlobalConfiguration.Configuration.Formatters.XmlFormatter.SupportedMediaTypes.Clear();} <br>

如许返回的效果就都是json范例了，但有个不好的处所，假如返回的效果是String范例，如123，返回的json就会变成"123";

处置惩罚的要领是自定义返回范例(返回范例为HttpResponseMessage)

public HttpResponseMessage PostUserName(User user)   
{   
String userName = user.userName;   
HttpResponseMessage result = new HttpResponseMessage { Content = new StringContent(userName,Encoding.GetEncoding("UTF-8"), "application/json") };   
return result;   
}

要领二：(万金油法)

要领一中又要改设置，又要处置惩罚返回值为String范例的json，甚是贫苦，不如就不必web api中的的自动序列化对象，本身序列化后再返回

public HttpResponseMessage PostUser(User user)   
{   
JavaScriptSerializer serializer = new JavaScriptSerializer();   
string str = serializer.Serialize(user);   
HttpResponseMessage result = new HttpResponseMessage { Content = new StringContent(str, Encoding.GetEncoding("UTF-8"), "application/json") };   
return result;   
}

要领二是我比较引荐的要领，为了不在每一个接口中都反复写那几句代码，所以就封装为一个要领如许运用就轻易多了。

public static HttpResponseMessage toJson(Object obj)   
{   
String str;   
if (obj is String ||obj is Char)   
{   
str = obj.ToString();   
}   
else   
{   
JavaScriptSerializer serializer = new JavaScriptSerializer();   
str = serializer.Serialize(obj);   
}   
HttpResponseMessage result = new HttpResponseMessage { Content = new StringContent(str, Encoding.GetEncoding("UTF-8"), "application/json") };   
return result;   
}

要领三：(最贫苦的要领)

要领一最简朴，但杀伤力太大，一切的返回的xml花样都会被毙掉，那末要领三就能够只让api接口中毙掉xml，返回json

先写一个处置惩罚返回的类：

public class JsonContentNegotiator : IContentNegotiator   
{   
private readonly JsonMediaTypeFormatter _jsonFormatter;   
  
public JsonContentNegotiator(JsonMediaTypeFormatter formatter)   
{   
_jsonFormatter = formatter;   
}   
  
public ContentNegotiationResult Negotiate(Type type, HttpRequestMessage request, IEnumerable<MediaTypeFormatter> formatters)   
{   
var result = new ContentNegotiationResult(_jsonFormatter, new MediaTypeHeaderValue("application/json"));   
return result;   
}   
}

找到App_Start中的WebApiConfig.cs文件，翻开找到Register(HttpConfiguration config)要领

增加以下代码：

var jsonFormatter = new JsonMediaTypeFormatter();   
config.Services.Replace(typeof(IContentNegotiator), new JsonContentNegotiator(jsonFormatter));

增加后代码以下：

<br>public static void Register(HttpConfiguration config) <br>{ <br>config.Routes.MapHttpRoute( 
<br>name: "DefaultApi", <br>routeTemplate: "api/{controller}/{action}/{id}", <br>defaults: new { 
id = RouteParameter.Optional } <br>);var jsonFormatter = new JsonMediaTypeFormatter();   
onfig.Services.Replace(typeof(IContentNegotiator), new JsonContentNegotiator(jsonFormatter));} <br>

要领三假如返回的效果是String范例，如123，返回的json就会变成"123"，处置惩罚要领同要领一。

实在web api会自动把返回的对象转为xml和json两种花样并存的情势，要领一与要领三是毙掉了xml的返回，而要领二是自定义返回。

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