Includes and templating.

Question

Hi, I am not sure quite how to ask this question, but what I want to know is the most effective way to include different aspx files to generate one page. Basically when I used previous ASP versions I would have a file header.asp, footer.asp and then each web page I created would include these two files (one at the top of the page and one at the bottom). I see no easy way to do this in C# web applications as when I include other ASPX files it gives all sorts of errors obviously because I have redeclarations of events or something of the sort. I assume there must be an easy way to do this as it would be very difficult to maintain large websites with out this fucntionality. Any Ideas?