asp.net MVC4下同时启用默认路由及Web API，以及针对WebAPI 考虑接口分版本问题

public class OPAPIVersionSelector:DefaultHttpControllerSelector
    {
        private HttpConfiguration _config;

        public OPAPIVersionSelector(HttpConfiguration config)
            : base(config)
        {
            _config = config;
        }
    
        //设计就是返回HttpControllerDesriptor的过程
        public override System.Web.Http.Controllers.HttpControllerDescriptor SelectController(HttpRequestMessage request)
        {
            //获取所有的controller键值集合
            var controllers = GetControllerMapping();
        
            //获取路由数据
            var routeData = request.GetRouteData();
        
            //从路由中获取当前controller的名称
            var controllerName = (string)routeData.Values["controller"];
        
            HttpControllerDescriptor descriptor = new HttpControllerDescriptor();
        
            //if(controllers.TryGetValue(controllerName, out descriptor))
            //{
                //var version = "2";
            
                //从QueryString中获取版本 
                var version = GetVersionFromQueryString(request);
            
                var newName = string.Concat(controllerName, "V", version);
            
                HttpControllerDescriptor versionedDescriptor;
            
                if(controllers.TryGetValue(newName, out versionedDescriptor))
                {
                    return versionedDescriptor;
                }
            
                return descriptor;
            //}
        
            return null;
        
        }
    
        //从QueryString中获取版本 
        private string GetVersionFromQueryString(HttpRequestMessage request)
        {
            string sPathAdnQuery = request.RequestUri.PathAndQuery.ToLower();
            if (!string.IsNullOrEmpty(sPathAdnQuery))
            {

                var arr = sPathAdnQuery.Split(‘/‘);
                if (arr.Length >= 5)
                {
                    if (arr[1] == "OpenApi" && arr[3].Contains("v"))
                    {
                        return arr[3].Substring(1);
                    }
                }

            }

            //var query = HttpUtility.ParseQueryString(request.RequestUri.Query);//此部分是要求版本作为参数传过来，而不是URL
            //var version = query["v"];
            //if(version != null)
            //{
            //    return version;
            //}
        
            return "1";
        }
    }

public static class WebApiConfig
    {
        public static void Register(HttpConfiguration config)
        {
            config.Routes.MapHttpRoute(
                name: "OPApiV1",
                routeTemplate: "OpenApi/{controller}/{ver}/{action}/{id}",
                defaults: new {  id = RouteParameter.Optional }

            );
            //config.Routes.MapHttpRoute(
            //    name: "OPApiV2",
            //    routeTemplate: "api/{controller}/v2/{action}/{id}",
            //    defaults: new { id = RouteParameter.Optional }

            //);
            //注册版本选择器
            config.Services.Replace(typeof(IHttpControllerSelector), new OPAPIVersionSelector(config));
        }
    }

WebApiConfig.Register(GlobalConfiguration.Configuration);

[HttpPost]
 public OPResponseBaseModel> GetUserAndDepartmentInfo([FromBody]OPRequestParamBaseModel requestModel)
 {
　　//your  code
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