As the title suggests, I want to add something to a table (inside aspx page) depending on some infos I get from a database (so if I have an item x in db I will make a bool type variable in cs).
My question is, is there any method to send that bool to aspx so I can use it inside an if statement (in order to add the respective columns to my table).
You don't need a session variable here, you can simply declare a class level property and use it in your ASPX page:-
public bool variable { get; set; }
and then directly use it in your aspx page:-
<%=variable %>