Class lib design advice

[Morton]

Hello,

I'm in the process of making a class library for communicating with a PLC.
I'm uncertain what would be the best design pattern to use. I've made some
experimentations with the aggregate component design pattern much like
SerialPort is build but the problem with this is that my class library is
using async sockets under the hood. The communication itself is ethernet
using .NET async sockets.

Therefore I need to have some sort of callback method. Right now I supply a
ResultCallback delegate to the publically exposed methods on my Plc class.
Forexample:

public void ReadBit(ResultCallback resultCallback, MemoryArea memoryArea,
short beginningAddress, short noItems, byte bit)

What this does is to return the result of the operation to the method that
resultcallback is pointing to. Where ResultCallback looks like this public
delegate void ResultCallback(object result)

The callback methods then casts the result to whatever the expected return
type is (boolean, short, int, etc).

Now I'm considering making it so that the user of the class library has to
create a PlcCommand object and then use Plc.Send(commandObject) and then
attach an eventhandler to the command object or some such.

I hope this gives you an idea what kind of library I'm making. Any
suggestions in terms of the design would be much appreciated.