你是怎么改变？如果您在使用任何一种源头控制，检查Web.config文件中的变化与的Global.asax.cs文件一起。路由模块会自动加载用于.NET Framework 4.0的项目。有一个小的机会，有人无意中改变了项目的目标框架版本。失去了路线的其他可能的崩溃是从Global.asax中的Application_Start事件处理程序的路由登记的RouteTable。

What did you change? If you are using any kind of source control, check the changes on web.config file along with global.asax.cs file. The routing module is automatically loaded for .NET Framework 4.0 project. There is a small chance that someone accidently changed the target framework version of the project. Other possible crash of losing the routes is the Routes registration with the RouteTable in the Application_Start event handler from the Global.asax.