pass value from view to controller

Question

i have this dropdown list

@Html.DropDownListFor(model => model.Contant.KEYWORD_NAME, ViewData["KEYWORD_NAME"] as IEnumerable<SelectListItem>, item.SelectedItemType, new { @class = "form-control" })

and i pass some data to view

@if (Model != null)
{
@Html.PagedListPager(Model.Items, page => Url.Action("search", new { page, search = Request.QueryString["search"], KEYWORD_NAME = Request.QueryString["Contant.KEYWORD_NAME"]}),
new PagedListRenderOptions()
{
Display = PagedListDisplayMode.IfNeeded,
DisplayPageCountAndCurrentLocation = true
,
DisplayItemSliceAndTotal = true
})

this is the header for the method

public ActionResult search(int? page, string search, string KEYWORD_NAME)

i have value for page and search m but for KEYWORD_NAMEits null

 

how i can fix it ?