如何强制ASP.NET Web API始终返回JSON？

Question

ASP.NET Web API默认执行内容协商 - 将根据Accept标头返回XML或JSON或其他类型.我不需要/想要这个,有没有办法(比如属性或东西)告诉Web API总是返回JSON？

Answer 1

清除所有格式化程序并添加Json格式化程序.

GlobalConfiguration.Configuration.Formatters.Clear();
GlobalConfiguration.Configuration.Formatters.Add(new JsonMediaTypeFormatter());

编辑

我把它添加到Global.asax里面Application_Start().

Answer 2

仅支持ASP.NET Web API中的JSON - 正确的方法

用JsonContentNegotiator替换IContentNegotiator:

var jsonFormatter = new JsonMediaTypeFormatter();
//optional: set serializer settings here
config.Services.Replace(typeof(IContentNegotiator), new JsonContentNegotiator(jsonFormatter));

JsonContentNegotiator实现:

public class JsonContentNegotiator : IContentNegotiator
{
    private readonly JsonMediaTypeFormatter _jsonFormatter;

    public JsonContentNegotiator(JsonMediaTypeFormatter formatter) 
    {
        _jsonFormatter = formatter;    
    }

    public ContentNegotiationResult Negotiate(
            Type type, 
            HttpRequestMessage request, 
            IEnumerable<MediaTypeFormatter> formatters)
    {
        return new ContentNegotiationResult(
            _jsonFormatter, 
            new MediaTypeHeaderValue("application/json"));
    }
}

Answer 3

Philip W有正确的答案,但为了清晰和完整的工作解决方案,编辑你的Global.asax.cs文件如下所示:(注意我必须将参考System.Net.Http.Formatting添加到库存生成的文件中)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http.Formatting;
using System.Web;
using System.Web.Http;
using System.Web.Mvc;
using System.Web.Optimization;
using System.Web.Routing;

namespace BoomInteractive.TrainerCentral.Server {
    // Note: For instructions on enabling IIS6 or IIS7 classic mode, 
    // visit http://go.microsoft.com/?LinkId=9394801

    public class WebApiApplication : System.Web.HttpApplication {
        protected void Application_Start() {
            AreaRegistration.RegisterAllAreas();

            WebApiConfig.Register(GlobalConfiguration.Configuration);
            FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
            RouteConfig.RegisterRoutes(RouteTable.Routes);
            BundleConfig.RegisterBundles(BundleTable.Bundles);

            //Force JSON responses on all requests
            GlobalConfiguration.Configuration.Formatters.Clear();
            GlobalConfiguration.Configuration.Formatters.Add(new JsonMediaTypeFormatter());
        }
    }
}

Answer 4

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

这会清除XML格式化程序,从而默认为JSON格式.