asp.net mvc - Cannot get Dropdownlist to work properly -

i want simple dropdownlist contains values "ascending" , "descending" sent controller sortorder when search button pressed in index() method. have tried many different things , cannot work, doing wrong.

p.s not want make model, want simple "asc" or "desc" dropdown sortorder variable.

usercontroller.cs

    public viewresult index( string searchstring, string sortorder = "asc")     {         var sortorderparam = new[]             {                 new selectlistitem { value = "asc", text = "ascending" },                 new selectlistitem { value = "desc", text = "descending" }             };          var users = u in db.tbl_sys_user                     select u;          if (!string.isnullorempty(searchstring))         {             users = users.where(x => x.user_first_name.toupper().contains(searchstring.toupper()));         }          switch (sortorder)         {             case "desc":                 users = users.orderbydescending(u => u.user_first_name);                 break;             default:                 users = users.orderby(u => u.user_first_name);                 break;         }          populatefielddropdownlist("");          return view(users.tolist());     } 

index.cshtml

@using (html.beginform()) {     <p>         search criteria: @html.textbox("searchstring")         order by: @html.dropdownlist("sortorderparam")          <input type="submit" value="search"/>     </p> } 

in controller action, should create list of dropdownlist options , pass them view in viewbag, or property of viewmodel. below:

public viewresult index(string searchstring, string sortorder = "asc") {     var users = u in db.tbl_sys_user                 select u;      if (!string.isnullorempty(searchstring))     {         users = users.where(x => x.user_first_name.toupper().contains(searchstring.toupper()));     }      switch (sortorder)     {         case "desc":             users = users.orderbydescending(u => u.user_first_name);             break;         default:             users = users.orderby(u => u.user_first_name);             break;     }      populatefielddropdownlist("");      var sortorderoptions = new list<selectlistitem>();     sortorderoptions.add(new selectlistitem { value = "asc", text = "ascending" });     sortorderoptions.add(new selectlistitem { value = "desc", text = "descending" });     viewbag.sortorderoptions = sortorderoptions;      return view(users.tolist()); } 

the first argument in html.dropdownlist method name of field (which name of value posted action), , second 1 ienumerable<selectlistitem> options in dropdownlist. so, view this:

@using (html.beginform()) {     <p>         search criteria: @html.textbox("searchstring")         order by: @html.dropdownlist("sortorderparam", viewbag.sortorderoptions)          <input type="submit" value="search"/>     </p> }