ASP.NET MVC从控制器中获取URL值

string value = Request.QueryString["BookId"].ToString();

#region 1、通过Request.QueryString的方式获取URL的值
public ActionResult Index()
{
       // 获取路由数据
       if (Request.QueryString["BookId"] != null)
      {
            string value = Request.QueryString["BookId"].ToString();
            ViewData["msg"] = value;
       }
       return View();
} 
#endregion

<p style="color:red;font-weight:bold">1、通过Request.QueryString获取URL的值：@ViewData["msg"]</p>

string paraDatas = string.Format("controller={0} action={1} id={2}", RouteData.Values["controller"].ToString(),
                RouteData.Values["action"].ToString(), RouteData.Values["id"]);

public ActionResult Index()
{
      // 获取路由数据
      string paraDatas = string.Format("controller={0} action={1} id={2}", RouteData.Values["controller"].ToString(),
                    RouteData.Values["action"].ToString(), RouteData.Values["id"]);
       ViewData["msg"] = paraDatas;
       return View();
}

<p style="color:blue;font-weight:bold">2、通过RouteData获取URL的值：@ViewData["msg"]</p>

public ActionResult Index(string controller, string action, int id)
{ }

public ActionResult Index(string controller, string action, int id)
{
      // 获取路由数据
      string paraDatas = string.Format("controller={0} action={1} id={2}", controller, action, id);
      ViewData["msg"] = paraDatas;
      return View();
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Web.Routing;

namespace MVCUrlPara
{
    public class RouteConfig
    {
        public static void RegisterRoutes(RouteCollection routes)
        {
            routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

            routes.MapRoute(
                name: "Default",
                url: "{controller}/{action}/{id}",
                defaults: new { controller = "Home", action = "Index", id = 2 } //给id默认值2
            );
        }
    }
}