Can you provide more details. Are you trying to protect plain asp code or asp.net code. From whom you are trying to protect, the person who has access to the file system to read your code or are you trying to prevent users from reading your code in web server. Pre-Compiling and publishing your code may help but the user who would be viewing this code would be authorised user of the web server, so there is no question of unauthorized user.

ASP or ASP.net code is never sent to the client browser but renders to pure HTML so there is no question of viewing the source code.

Hope this gives you some idea or please elaborate your requirement.