ASP.NET and Javascript DOM manipulation

Question

I have an aspx page with a set of controls.

A small JS script written on top of jQuery allows the user to drag "li" elements from one list to another.

What I would like now is for my C# code to be able to figure out which items the user has placed in which list after the page is posted back to the server.

Does anyone know how I can do this?

Thanks.

Answer 1

Without some specifics, its hard to get into details. But for ASP.NET server-side controls, the trick is properly maintaining viewstate (or just bypassing it). So strategically you've got two fundamental options:

1) Track the changes server-side by using AJAX to push updates to the server.

2) Track the data client-side by updating some element ASP.NET could understand. My personal favorite is to use a hidden form field that I add a user's "moves" to in a format that can be replayed in my web form.

Answer 2

The easiest way to do it would be to add a HiddenField to your page. Whenever the lists change, populate the HiddenField's value accordingly. When a postback occurs, the HiddenField's value will be available on the server side.

Answer 3

What i've done in the past with drag & drop functionality in ASP.NET, is read the DOM elements via jQuery, and do an AJAX postback with the values in those DOM elements as a parameter.