<tr>
    <th>
        @Html.ActionLink("Last Name", "Index", new { sortOrder = ViewBag.NameSortParm })
    </th>
    <th>First Name
    </th>
    <th>
        @Html.ActionLink("Enrollment Date", "Index", new { sortOrder = ViewBag.DateSortParm })
    </th>
    <th></th>
</tr>