|Thank you jschell. I appreciate your involvement.
Apologies, if perhaps I haven't made myself clear.
As per my post above, I've mentioned that I am using external dll. Therefore, I use namespace to it, exactly as per your suggestion. So in my Form1 I can access all methods from my external class library.
To be clear, this is an external dll class for my sockets client.
OnReceive(IAsyncResult ar) I need to display value on label.text in my Form1, or other forms where I will be using my external sockets class dll assembly.
Another method within that class need to call method from Form1 checkCommand(string command). Hope this will help explaining it better
Thank you again