Select2: Set Default value for list of dropdown items, data obtained from C# Model in razor syntax

Question

I have a select2 drop down and I want to select default values for the list items. It works fine when I use hard code values for setting the default values of the dropdown like this $('#PlatFormTitle').val(['1','2','3']);

But I want to select values based on the data obtained from the model. Here is the code I am trying can someone please identify what am I doing wrong here.

    var PlateForms = [];

    var x;
    @foreach(var PlateForm in Model.UserPlateFormList)
    {
        @:x = '@PlateForm';
        @:PlateForms.push(x);
    } 
    $('#PlatFormTitle').val(PlateForms);
    $('#PlatFormTitle').trigger('change');

I tried this as well.

$('#PlatFormTitle').val(JSON.stringify(PlateForms));
$('#PlatFormTitle').trigger('change');

Answer 1

I test with your code,and it can work,here is the demo:

Model:

public class Model1 {
        public List<int> UserPlateFormList { get; set; }
    }

Controller:

public IActionResult Index()
        {
            Model1 m = new Model1 { UserPlateFormList = new List<int> { 1, 2, 3 } };
            return View(m);
        }

View:

<select id="PlatFormTitle" class="js-example-basic-multiple" multiple="multiple" style="width:200px">
    <option value='1'>1</option>
    <option value='2'>2</option>
    <option value='3'>3</option>
    <option value='4'>4</option>
    <option value='5'>5</option>
    <option value='6'>6</option>
</select>

js:

<script src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.13/js/select2.min.js"></script>
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.13/css/select2.min.css" />
 <script>
        $(function () {
            $('.js-example-basic-multiple').select2();
            var PlateForms = [];
            var x;
            @foreach (var PlateForm in Model.UserPlateFormList)
            {
                @:x = '@PlateForm';
                @:PlateForms.push(x);
            }
                $('#PlatFormTitle').val(PlateForms);
                $('#PlatFormTitle').trigger('change');
        });
</script>

result: