I'm trying to make my view sortable by table's menu items.

here's my controller

```
 public ActionResult Index(string sortOrder)
        {
            ViewBag.NameSortParm = "name";
            ViewBag.descSortParm = "description";
            ViewBag.beginDateSortParm = "beginDate";
            ViewBag.endDateSortParm = "endDate";
            ViewBag.priceSortParm ="price";

            var persons = from s in db.PRT_FEE_PRICES
                          select s;
            switch (sortOrder)
            {
                case "name":
                    persons = persons.OrderBy(s => s.NAME);
                    break;
                case "description":
                    persons = persons.OrderBy(s => s.DESCRIPTION);
                    break;
                case "beginDate":
                    persons = persons.OrderBy(s => s.BEGIN_DATE);
                    break;
                case "endDate":
                    persons = persons.OrderBy(s => s.END_DATE);
                    break;
                case "price":
                    persons = persons.OrderBy(s => s.PRICE);
                    break;
                default:
                    persons = persons.OrderBy(s => s.NAME);
                    break;
            }

            return View(persons.ToList());
        }

```

and here's view

```
<table class="table">
    <tr>
        <th>
            @Html.ActionLink("სახელი", "Index", new { sortOrder = ViewBag.NameSortParm })
        </th>
        <th>
            @Html.ActionLink("აღწერა", "Index", new { sortOrder = ViewBag.descSortParm })
        </th>
        <th>
            @Html.ActionLink("დაწყების თარიღ", "Index", new { sortOrder = ViewBag.beginDateSortParm })
        </th>
        <th>
            @Html.ActionLink("დამთავრების თარიღი", "Index", new { sortOrder = ViewBag.endDateSortParm })
        </th>
        <th>
            @Html.ActionLink("ფასი", "Index", new { sortOrder = ViewBag.priceSortParm })
        </th>
        <th></th>
    </tr>

    @foreach (var item in Model)
    {
        <tr>
            <td>
                @Html.DisplayFor(modelItem => item.NAME)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.DESCRIPTION)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.BEGIN_DATE)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.END_DATE)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.PRICE)
            </td>

        </tr>
    }

</table>

```

it works perfect sorts everything. How can I do that on second click it sorts these fields by descending? I have no idea how to do that?