public IEnumerable<string> Get();
public string Get(int id);
public void Post([FromBody]string value);
public void Put(int id, [FromBody]string value);
public void Delete(int id);

public class MyResponse
    {
        public int ErrCode { get; set; }
        public string ErrMsg { get; set; }
        public object Data { get; set; }
    }

public MyResponse Get();
public MyResponse Get(int id);
public MyResponse Post([FromBody]string value);
public MyResponse Put(int id, [FromBody]string value);
public MyResponse Delete(int id);

public MyResponse Get(int id)
{
            var model = UserRepository.Find(id);
            return new MyResponse()
            {
                Data = model
            };
 }

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