@addTagHelper*, Microsoft.AspNetCore.Mvc.TagHelpers
@model SelectList
@{
    ViewData["Title"] = "Home Page";
}

<div class="text-center">
    <h1 class="display-4">Welcome</h1>  
</div>
<select id="ddlCustomers" name="CustomerId" asp-items="Model">
    <option value="0">--Select Customer--</option>
</select>
<form method="post" asp-controller="Home" asp-action="Index">

    <br />
    <br />
    <input type="submit" value="Submit" />
    @if (ViewBag.Message != null)
    {
        <script type="text/javascript">
            window.onload = function () {
                alert("@ViewBag.Message");
            };
        </script>
    }

</form>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/select2@4.0.13/dist/css/select2.min.css" />
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script type="text/javascript" src="https://cdn.jsdelivr.net/npm/select2@4.0.13/dist/js/select2.min.js"></script>
<script type="text/javascript">
    $(function () {
        $("#ddlCustomers").select2();
    });
</script>