ASP.NET 4 HttpHandler in Custom Route

I have made a custom Route which override GetRouteData. How can I know what type of request is being done? Everything passes the GetRoutData function (.cs开发者_如何学Pythons, .js, .axd, etc) and I would like to do something only if it is a System.Web.UI.Page.

But httpContext.Request.CurrentHandler is always null because the routing takes place just before the handler mapping...

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any reason you can't limit your route to .aspx files? Do you not want to handle pages that superclass ui.page?