asp.net webapi 返回json结果的方法

第一种：

        public static void Register(HttpConfiguration config) {

            //1、将默认的xml格式化程序清除
            GlobalConfiguration.Configuration.Formatters.XmlFormatter.SupportedMediaTypes.Clear();

            //2、设置默认返回json格式的数据
            GlobalConfiguration.Configuration.Formatters.JsonFormatter.MediaTypeMappings.Add(new QueryStringMapping("dataType","json","application/json"));            

            //3、如果设置http://xxx?dataType=xml，则返回xml格式的数据
            GlobalConfiguration.Configuration.Formatters.JsonFormatter.MediaTypeMappings.Add(new QueryStringMapping("dataType", "xml", "application/xml"));

            // Web API 配置和服务

            // Web API 路由
            config.MapHttpAttributeRoutes();

            config.Routes.MapHttpRoute(
                name: "DefaultApi",
                routeTemplate: "api/{controller}/{id}",
                defaults: new { id = RouteParameter.Optional }
            );

            config.Routes.MapHttpRoute(
               name: "DefaultApi2",
               routeTemplate: "api/{controller}/{action}/{id}",
               defaults: new { id = RouteParameter.Optional }
           );
        }
    }

Action的使用方式：

        [AcceptVerbs("GET", "POST")]        
        [Route("FetchList")]
        public Resultx FetchList() {
            return new Resultx { Code = 0, Message = "OK", Result = new { name="list",list=new List<string> { "1","2"} } };
        }

第二种：

        [AcceptVerbs("GET", "POST")]
        [Route("FetchList")]
        //使用IHttpActionResult接口，用JsonResult<>()来返回Json字符串
        public IHttpActionResult FetchList() {
            return Json(new { Code = 0, Message = "OK", Result = new { name = "list", list = new List<string> { "1", "2" } } });
        }

以上两种结果都能正常返回Json字符串：

{"Code":0,"Message":"OK","Result":{"name":"list","list":["1","2"]}}