I would like to store some information in the cache that I can compare later on with those that the user has typed in. Should I use HttpModule or HttpHandler?? Or is there any better way to do this in WebForms?? I know that in MVC ActionFilters can be used.
Try to use session state:
// Save to session state in a Web Forms page class.
Session["FirstName"] = firstName;
Session["LastName"] = lastName;
Session["City"] = city;
// Read from session state in a Web Forms page class.
firstName = (string)(Session["FirstName"]);
lastName = (string)(Session["LastName"]);
city = (string)(Session["City"]);