WebAPI跨域

 public static class WebApiConfig
    {
        public static void Register(HttpConfiguration config)
        {
            //跨域配置
            config.EnableCors(new EnableCorsAttribute("*", "*", "*"));
            // Web API 路由
            config.MapHttpAttributeRoutes();
            config.Routes.MapHttpRoute(
                name: "DefaultApi",
                routeTemplate: "api/{controller}/{action}/{id}",
                defaults: new { id = RouteParameter.Optional }
            );
        }
    }

            #region 跨域
            services.AddCors(options =>
            {
                // Policy 名稱 CorsPolicy 是自訂的，可以自己改
                options.AddPolicy("CorsPolicy", policy =>
                {
                    policy.AllowAnyOrigin()
                            .AllowAnyHeader()
                            .AllowAnyMethod()
                            .AllowCredentials();
                });
            });
            #endregion

            // 启用跨域
            app.UseCors("CorsPolicy");