1. 增加一个WebApi Controller, VS 会自动添加相关的引用，主要有System.Web.Http，System.Web.Http.WebHost，System.Net.Http

2. 在App_Start 下创建 WebApiConfig.cs 并注册路由

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Web.Http;namespace Libaray.Web.App_Start{    public static class WebApiConfig    {        public static void Register(HttpConfiguration config)        {            // 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 }            );        }    }}

3. 在Global.asax， Application_Start 下添加 WebAPI 配置

using Libaray.Web.App_Start;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 Libaray.Web{    public class MvcApplication : 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);        }    }}

4. 在第一步添加的WebApi 中填写相应代码， 

using Libaray.Web.Models;using System;using System.Collections.Generic;using System.Linq;using System.Net;using System.Net.Http;using System.Web.Http;namespace Libaray.Web.Controllers{    [RoutePrefix("api/SystemUsers")]    public class SystemUsersController : ApiController    {        [HttpGet, Route("GetUserList")]        public List
     
       GetUserModels()        {            UserModelService UserBS = new UserModelService();            return UserBS.FindList(u => u.isActive == true);        }        [HttpGet, Route("GetUser")]        public UserModel GetUserModel(int id = 0)        {            if(id != 0)            {                UserModelService UserBS = new UserModelService();                return UserBS.Find(u => u.Id == id);            }            else            {                return null;            }        }        [HttpPost, Route("Login")]        public bool Login(string loginId,string password)        {            UserModelService UserBS = new UserModelService();            return UserBS.ValidateLoginInfo(loginId, password);        }    }}
     

5. Run the application and call the API. Example: http://localhost:49919/api/SystemUsers/GetUserList