How to handle Postback

i have a web form in which i let users to fill some fields, after user has filled some fields there is a button for Add which opens a new page and fill the form on that page after the user submits that form he checks the submit button and there is a function from database called to fill the dropdownlist on the first page, it is done without with no problem but the issue is that when the user submits the second form and the first page dropdownlist is populated with values from database it performs a postback and the values in the fields already submitted by the user is lost after postback,i know i can do that using viewstate but is there any option which i can do to retain the values thanks