MVC - Check drowdownlist value in real time

Question

How can I check the dropdownlist selectedvalue in real time in MVC, everytime the selected value is changed?

<div class="modal-body">
     Ticket Category:     @Html.DropDownList("TicketCategory", (SelectList)ViewBag.TicketCategory, "--Select Category--")
    </div>
    @if(TicketCategory.SelectedValue == "")
    {
        //do
    }
    else
    {
        //do 
    }

In this case the TicketCategory is not found, am I missing some conversion or do I have to retrieve the element?

Answer 1

For DropDownList you have an extra parameter for declaring some htmlAttributes.

From my point of view you always must flag your inputs that you're listening to with some js-smth class.

RAZOR:

<div class="modal-body js-modalBody">
     Ticket Category:     @Html.DropDownList("TicketCategory", (SelectList)ViewBag.TicketCategory, "--Select Category--",  new { @class = "js-ticketCategory" })
</div>

After this you can add a script tag, listening to change event of the input. Assuming that you search for a value that is "3", here is your code.

<script>

$('.js-modalBody').on('change', '.js-ticketCategory', function (ev) {
    if ($(ev.currentTarget).val() == "3") {
        // do something 
    } else {
        // do something else 
    }
});

</script>

P.S: Having javascript in your views isn't a beatiful approach.