In order to run a method on a object at runtime, that object
(or class definition and prototype for the class) must be in the
Flash Player. There are several ways to get it there.
One is to compile the definition into the SWF. This is the
normal and default way. If your class is in a SWC, you would add
the SWC to the library path and its definition will be added to the
Another way is to place the SWC into a separate SWF and
download the SWF at runtime, bringing the definition into the Flash
Player. Only SWFs can be downloaded at runtime, not SWCs. So you
need to build a SWF from the SWC. The Flex docs can give you
insight about this. You can load the SWF using the Loader,
SWFLoader, Modules, and Runtime Shared Libraries.
There is no magic or simpler way to do this. If you tell the
SWF compiler that a class will be defined at runtime, the SWF will
contain references to the class, but not the definition. If you try
to execute the methods of the class, you will get a runtime error -
it will not be automatically downloaded - you will have to write
code to do that.