using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http.Formatting;
using System.Web;
using System.Web.Http;
using System.Web.Security;
using System.Web.SessionState;

namespace AS.GroupOn.Web
{
    public class Global : System.Web.HttpApplication
    {

        protected void Application_Start(object sender, EventArgs e)
        {
            WebApiConfig.Register(GlobalConfiguration.Configuration); 
        }

        public override void Init()
        {
            this.PostAuthenticateRequest += MvcApplication_PostAuthenticateRequest;//用于打开session
            base.Init();
        }

      void MvcApplication_PostAuthenticateRequest(object sender, EventArgs e)
        {
            System.Web.HttpContext.Current.SetSessionStateBehavior(
                SessionStateBehavior.Required);
        }
    }

    public static class WebApiConfig
    {
        public static void Register(HttpConfiguration config)
        {

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

            config.Routes.MapHttpRoute(
                name: "DefaultApi",
                routeTemplate: "api/{controller}/{id}",
                defaults: new { id = RouteParameter.Optional }
            );
            GlobalConfiguration.Configuration.Formatters.XmlFormatter.UseXmlSerializer = true;//设定返回方式

            // config.Formatters.JsonFormatter.AddQueryStringMapping("$format", "json", "application/json");
            //config.Formatters.XmlFormatter.AddQueryStringMapping("$format", "xml", "application/xml"); 
            //config.Formatters.Remove(config.Formatters.JsonFormatter);
            //config.Formatters.Remove(config.Formatters.XmlFormatter);
            // 取消注释下面的代码行可对具有 IQueryable 或 IQueryable<T> 返回类型的操作启用查询支持。
            // 若要避免处理意外查询或恶意查询，请使用 QueryableAttribute 上的验证设置来验证传入查询。
            // 有关详细信息，请访问 http://go.microsoft.com/fwlink/?LinkId=279712。
            //config.EnableQuerySupport();

            // 若要在应用程序中禁用跟踪，请注释掉或删除以下代码行
            // 有关详细信息，请参阅: http://www.asp.net/web-api
            //  config.EnableSystemDiagnosticsTracing();
        }
    }
}

using System.Net;
using System.Net.Http;
using System.Web;
using System.Web.Http;

 private HttpResponseMessage getReturnMessage(int sta, string msg, HttpStatusCode httpStatus = HttpStatusCode.MethodNotAllowed)
        {
            return Request.CreateResponse(httpStatus, new{status=sta,info=msg});
        }

        private HttpResponseMessage getReturnMessage(int sta,object obj, HttpStatusCode httpStatus = HttpStatusCode.OK)
        {
            return Request.CreateResponse(httpStatus, new { status = sta, obj});
        }