You should set the values from the database to any of the input controls.If you don't want to set in hidden field use like below.
Create a div and add a style display:none to the div and place the remaining fields inside the div and set all the values in textBoxes.
<div style="display:none">
//Set your remaining input field here
</div>
I think there is no problem of using hiddenfield because your are using post method.It is a secured method.
Hope this helps