To check a string contains specific word(here its user).

Hi,

I need to check a string contains a specific user. If user exist, need to enable button else disable it. I have used two strings. One hard coded and other taking the user name once a user logged in. And i need to check the user name in the list of hardcoded string.

here is what i have written. But its not correct.

Eg:

string username can take "xyzcom\\design.department" then the button should be shown.