crystal report using user inputs?

i am developing a web base application and report using crystal report in(C#,ASP.net,sql server 2005),
i want to develop crystal report based on the value of user inputs,
i have crystal report, and button show, and textbox1 for user input.
my sql statement is:
select fname,lname, code where department=user input
it looks like it is working..
but when i enter the name of the department on the textbox and enter the button show, it automatically shows me, parameter field(s)
department
value...<textbox here> <submit button here>
then i enter department then hit the submit button then it works..
my question is i didnot create a button with name submit, it automaticaly creates the above listed things.
any ideas, if you got me what i am talking about? where does it come these things, the submit button and the other things with it?
share your knowledge please