html helper

<div class="field-wrap">

  @Html.TextBoxFor(model => model.Username, new { @class = "form-control", id = "SignupUsername" , placeholder = "Username", @required = "required", autofocus = "" })

  @Html.ValidationMessageFor(model => model.Username, "", new { @class = "text-danger" })

</div> 

controller::>>

  var employees = GetEmployees();

            ViewBag.categorylist = new SelectList(employees, "Id", "Name");

html

     @Html.DropDownListFor(model => model.Item2, ViewBag.categorylist as SelectList, "---SelectList--", new { onchange = "rahul()" })