Is it considered cheating if you post assignment questions on a site but no one answered it If you post an assignment question on a 3rd party site. But got no answers from it.
Is that still considered cheating?
At my university, the answer is definitely yes. The rules here clearly state that even the attempt to cheat is misconduct (e.g. bringing a device that is capable of cheating to an exam is considered cheating even if it not used/touched).

(However, if asking a question about your assignment in some forum is cheating, depends on the rules for your course/institution. In my courses, this would not be forbidden for homework assignments, for example.)