>>Thanks for yuour replies.
>>I went ahead and changed a .cs file , did an IISRESET, and changes seemed to take effect.
>>So the .cs file must be run in real time ?
>>I realise thai is not the most ideal way but I was just curious !!
>
>I think this is what we call In-Place compilation. But, I would definitely suggest to remove those from the server and only use a DLL. This is better for security, provides less files to maintain, faster to update and usually is required by the security of the corporate standard to avoid those source files to be stored on the server.

I would guess this is not a Web Application Project since if I remember correctly the App_Code folder is not allowed for that type project. This would mean his project does not compile into a single dll, but rather a bunch of random named dll's. I am not actually sure if the code in the App_Code folder gets compiled with a build or not. Best solution is to use Web Application Projects, and compile all of it into a dll.
Tim