class and quikes?

Hello friends

I have class.vb and all client see same string in class.vb.. is it right ? My code is below. But all client should see their string.. different string.. How can i do this ? i can do this with quikes ? How can i write quikes for below code lines. my code dont let dublicate inserting...

Sincerely

my class is below

Public Class MyClass
Public Shared block As ...