WebForms使用System.Web.Routing

老赵同学写过 在Web应用程序开发过程中利用ASP.NET MVC框架的实战技巧 ，Routing现在可以作为URLRewriting技术的替代者，出现在asp.net mvc框架中，将它应用于WebForms上也是很简单的，可以到codeplex上下载ASP.NET MVC WebFormRouting Demo。

实现的原理也是很简单的：

1、创建一个自定义的实例化你的页面的 IRouteHandler 

     1: public class WebFormRouteHandler : IRouteHandler {

        public WebFormRouteHandler(string virtualPath)
            : this(virtualPath, true) {
        }

        public WebFormRouteHandler(string virtualPath, bool checkPhysicalUrlAccess) {
            if (virtualPath == null) {
                throw new ArgumentNullException("virtualPath");
            }

            if (!virtualPath.StartsWith("~/")) {
                throw new ArgumentException("virtualPath must start with a tilde slash: \"~/\"", "virtualPath");
            }

            this.VirtualPath = virtualPath;
            this.CheckPhysicalUrlAccess = checkPhysicalUrlAccess;
        }

        /// <summary>
        /// This is the full virtual path (using tilde syntax) to the WebForm page.
        /// </summary>
        /// <remarks>
        /// Needs to be thread safe so this is only settable via ctor.
        /// </remarks>
        public string VirtualPath { get; private set; }

        /// <summary>
        /// Because we're not actually rewriting the URL, ASP.NET's URL Auth will apply
        /// to the incoming request URL and not the URL of the physical WebForm page.
        /// Setting this to true (default) will apply URL access rules against the
        /// physical file.
        /// </summary>
        /// <value>True by default</value>
        public bool CheckPhysicalUrlAccess { get; set; }

        public IHttpHandler GetHttpHandler(RequestContext requestContext) {
            string virtualPath = GetSubstitutedVirtualPath(requestContext);
            if (this.CheckPhysicalUrlAccess && !UrlAuthorizationModule.CheckUrlAccessForPrincipal(virtualPath, requestContext.HttpContext.User, requestContext.HttpContext.Request.HttpMethod))
                throw new SecurityException();

            var page = BuildManager.CreateInstanceFromVirtualPath(virtualPath, typeof(Page)) as IHttpHandler;
            if (page != null) {
                //Pages that don't implement IRoutablePage won't have the RequestContext
                //available to them. Can't generate outgoing routing URLs without that context.
                var routablePage = page as IRoutablePage;
                if (routablePage != null)
                    routablePage.RequestContext = requestContext;
            }
            return page;
        }

        /// <summary>
        /// Gets the virtual path to the resource after applying substitutions based on route data.
        /// </summary>
        /// <param name="requestContext"></param>
        /// <returns></returns>
        public string GetSubstitutedVirtualPath(RequestContext requestContext) {
            if (!VirtualPath.Contains("{"))
                return VirtualPath;

            //Trim off ~/
            string virtualPath = VirtualPath.Substring(2);

            Route route = new Route(virtualPath, this);
            VirtualPathData vpd = route.GetVirtualPath(requestContext, requestContext.RouteData.Values);
            if (vpd == null)
                return VirtualPath;
            return "~/" + vpd.VirtualPath;
        }
    }

2、使用自定义的 IRouteHandler注册一个新的Routes

public class Global : System.Web.HttpApplication
    {

        protected void Application_Start(object sender, EventArgs e)
        {
            RegisterRoutes(RouteTable.Routes);
        }

        public static void RegisterRoutes(RouteCollection routes)
        {
            //We are intentionally creating this backdoor as a demonstration of
            //bad security practices.
            routes.MapWebFormRoute("Secret", "BackDoor", "~/Admin/SecretPage.aspx", false);
            routes.MapWebFormRoute("Blocked", "FrontDoor", "~/Admin/SecretPage.aspx", true);

            //Even though we are not checking physical url access in this route, it should still block because the incoming
            //request url would start with /Admin.
            routes.MapWebFormRoute("Admin", "Admin/{*anything}", "~/Admin/SecretPage.aspx", false);

            routes.MapWebFormRoute("Named", "foo/bar", "~/forms/blech.aspx");
            routes.MapWebFormRoute("Numbers", "one/two/three", "~/forms/haha.aspx");

            //Maps any requests for /haha/*.aspx to /forms/hahah.aspx
            routes.MapWebFormRoute("Substitution", "haha/{filename}", "~/forms/haha.aspx");
        }
    }

msdn杂志文章：
使用 ASP.NET Web 窗体路由：http://msdn.microsoft.com/zh-cn/magazine/2009.01.extremeaspnet.aspx