需要MVC路由帮助

routes.MapRoute(
      "Default1",                                   
      "",                           
      new { controller = "PostController", action = "Index", dynamicBlogName = ""} 
);
routes.MapRoute(
      "Default2",                                             
      "{dynamicBlogName}",                          
      new { controller = "PostController", action = "Index", dynamicBlogName = ""  } 
);
routes.MapRoute(
      "Default3",                                         
      "post/{dynamicPostName}",                           
      new { controller = "PostController", action = "Default", dynamicBlogName = "", dynamicPostName="" }
);
routes.MapRoute(
      "Default4",                                            
      "{dynamicBlogName}/post/{dynamicPostName}",            
      new { controller = "PostController", action = "Default", dynamicBlogName = "", dynamicPostName=""  }
);