How to do a dual listbox set up in ASP.Net MVC?

This may be silly, but trying to do a dual list box in ASP.Net MVC. I have the client side part working fine with options moving开发者_运维百科 back and forth, but what I would like is for the person to be able to save when they are done. This means I have to post all of the values in the "selected" list box. I don't want to rely on the user leaving the items selected, so do I have to pre-select them using the onsubmit of the form or the onclick of the button? Or am I missing something obvious?

I would use jQuery to get the list items and submit them as a custom postback