如何在asp.net中使用select2返回下拉列表的值？

Question

I am currently learning front-end development in asp.net and I seem to be lacking some fundamental understanding when it comes down to dropdownlists in particular. My goal is what I thought should be very straight forward and simple - to produce a multi-select, Select2 dropdownlist which posts back the values of the chosen select list items.

For some reason I simply cannot figure out how to do this, despite reading MS documents and similar StackOverflow questions. I can produce the dropdown, select the items, and even return a single value. But I can't get the value of the item/s before submitting (for js processing) so that I can return a list (or concatinated string) of all selected values.

My code is below, you can see in the javascript I have been attempting to access the value/s in different ways, but the value doesn't even get set on the li in the inspect element.

It would be great if someone could explain how to form this dropdownlist correctly so that I can retrieve the values I need (aka "80" and "81").

Controller

public ActionResult About()
        {
            AboutViewModel viewModel = new AboutViewModel();

            viewModel.Movies = new List<SelectListItem>()
            {
                new SelectListItem()
                {
                    Text = "Honey I Shrunk The Kids",
                    Value = "80"
                },
                new SelectListItem()
                {
                    Text = "Shrek 2",
                    Value = "81"
                }
            };
            return View(AboutViewPage, viewModel);
        }

[HttpPost]
public ActionResult About(AboutViewModel viewModel)
{
    return View();
}

View

   <div>
        @using (Html.BeginForm("About", "Home"))
        {

            @Html.DropDownList("Result", new SelectList(Model.Movies, "Value","Text"), new { @class = "values js-example-basic-single", @multiple = "multiple", @Id="movies" });

            <input type="submit" value="Submit" class="submit" onclick="collectMovies();" />
        }

    </div>



    <script>
        function collectMovies() {
            var test1= $('.select2-selection__choice').val();
            var testString = "";

            for (var i = 0; i < test1.length; i++) {
                testString += test1[i];
            }
        }


        $(document).ready(function () {
            $('.js-example-basic-single').select2();
        });
    </script>

Answer 1

When a multiple select control is posted to the server, the collection of selected values are processed by ASP.NET into a comma-separated list. The MVC model binding system quite happily sees this collection as an array. If the selected values can be parsed into ints, you can use an int array to represent the posted values

public class AboutViewModel 
{
   public int[] Result {get;set;}
}

[HttpPost]
public ActionResult About(AboutViewModel viewModel)
{
    return View();
}

Source