Question

شما نمیتوانید با لباس کار وارد رستوران شوید.

Answer 1

You aren't allowed to go in/ enter the restaurant in your work clothes.

You aren't allowed to go in/ enter the restaurant with your work clothes on.

You are prohibited from entering the restaurant in your work clothes.

 

Do not enter the restaurant in your uniform.

Answer 2

Also,

working wardrobe

workwear

working outfit

 

Answer 3

Hi

Besides other friends' nice answers:

You are forbidden to enter the restaurant in smock / overall.

smock : http://goo.gl/LVXm5S

overall : http://goo.gl/oCcm1X

More information on the difference between "ban , forbid & prohibit" : http://goo.gl/VI0N9F