>my employees have to make programs for which i need them to use some classes which i have created. is it possible for them not to be able to see the source and still use them.

You can compile them into an App and distribute them to your employees. They simply need to set classlib appropriately. Or you could compile your class libraries, make a copy of them (for backup purposes), open them as tables and delete the contents of the Methods field. Give your employees this version. As long as they don't try and recompile it, the compiled code in the ObjCode field will still remain for them to use.

HTH.