New Post: problem on MEF Winform load plugin DLL

i am new the MEF, i have a winform project and a class DLL project.

i wish not to add the DLL in the winform project, and trying to use MEF to export my class DLL project and import the DLL to winform project.

Could you please guide me step by step how should i need to do?

my class DLL project is

public class UpdateKeyword

how should i export this DLL and import to my WinForm? i am so confusing...