I'm replacing an existing asp.net app, with an asp.net mvc app. The old app used a lot of querystring params, and I need to map those into controller actions, everytime I stick  ? or & into a route i get a runtime error.

 Here's what I'm trying to do.

www.myapp.com/Products/Review.aspx?prodID=1456 should be replaced by something more RESTful, but I need to maintain backwards compatibility because of SEO, bookmarks, favorites, etc.

 I tried,

RouteTable.Routes.Add(new Route("Product/Reviews.aspx?productID={productID}", new MvcRouteHandler())
{
    Defaults = new RouteValueDictionary(new {controller="Reviews", action = "List"}),
});

The list action takes an int called productID.

You don't need to route them, they'll get passed to the controller.as-is (as params to the action if you name them such)

e.g. . . . .Add(new Route("Product/Reviews.aspx"),new MvcRouteHandler())  do the rest as you have it.  Then in your controller,

public void List(string productID){...}

Paul

would it be best to maybe have the old url's give an HTTP 301 Moved Permanently response header thingy? this way Search Engines are updated?