public class MyHttpModule:IHttpModule
    {
        #region IHttpModule 成员

        public void Dispose()
        {
           
        }

        public void Init(HttpApplication context)
        {
            context.BeginRequest += Application_BeginRequest;  
          
        }

        private void Application_BeginRequest(object sender, EventArgs e)
        {
            HttpApplication application = (HttpApplication)sender;
            HttpContext context = application.Context;

            string url = context.Request.RawUrl;
            if (!context.Request.RawUrl.Contains(".aspx"))
            {
                //你想要的操作
            }
            context.RewritePath(url);
        }  

        #endregion
    }