@model IList<Guid>
@{
    object attributes;
    if (ViewBag.Disabled == true)
    {
        attributes = new { @class = "form-control formultiselect2", @disabled = "disabled" };
    }
    else
    {
        attributes = new { @class = "form-control formultiselect2" };
    }
}
@Html.DropDownList(string.Empty, (IList<SelectListItem>)ViewData["List"], attributes)