转自：http://blog.ysatech.com/post/2010/07/11/ASP-NET-4-URL-Routing-Default-Page.aspx

Problem

I was implementing ASP.NET routing features for one of the web application. The code was working correctly in the development environment. Then I deployed it to staging server, navigate to http://mydomain.com/ and received the error 

"404 File Not Found". 

I tried to include routes.MapPageRoute("Default", "/", "~/Default.aspx"); in the global.asax file but I received another error 

"The route URL cannot start with a '/' or '~' character and it cannot contain a '?' character.Parameter name: routeUrl".

After several trials and errors, I found out that we should leave the "URL with parameters" empty. See below. 

routes.MapPageRoute("Default", "", "~/Default.aspx"); 

I hope you all will find this information useful.