默认webapi 不开启 session 会话支持
所以需要修改配置，手动在 Global 开启 session 支持 1.重写 init() 方法 2.开启session支持
Global.asax
using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Http; using System.Web.Mvc; using System.Web.Optimization; using System.Web.Routing; namespace WebApiCORS { public class WebApiApplication : System.Web.HttpApplication { protected void Application_Start() { AreaRegistration.RegisterAllAreas(); GlobalConfiguration.Configure(WebApiConfig.Register); FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters); RouteConfig.RegisterRoutes(RouteTable.Routes); BundleConfig.RegisterBundles(BundleTable.Bundles); } public override void Init() { //注册事件 this.AuthenticateRequest += WebApiApplication_AuthenticateRequest; base.Init(); } //开启session支持 void WebApiApplication_AuthenticateRequest(object sender, EventArgs e) { //启用 webapi 支持session 会话 HttpContext.Current.SetSessionStateBehavior(System.Web.SessionState.SessionStateBehavior.Required); } } }