Hi! I'm senior lectrurer on databases with 10+ years experience in MS SQL Server.
About different in triggers and sp. trigger can be executed on before/after update, delete, insert and included some actions, this action also can be presented as calling of sp.
Also I work with c# and doing desktop application. So, may be I'm not good for you, because I don't know asp.net very well. But you can tell me task, may be I can help you.