We all know about magic App_Code folder. Just drop class file in there and it will become a part of the web application. This is fine for scripts like PHP or "classic" ASP (VB script), but C# is strongly typed compiled language. How App_Code works? As any magic, mostly smoke and mirrors. Behind the scene, ASP.NET will create App_Code.dll and merge it with main application assembly at run time. This simple trick gives us best of both worlds - dynamism of scripting languages (ok, to the point) and all the good stuff coming with strong typing and compilation (whatever they are). More...