title: Extension methods cannot be dynamically dispatched
body: <p>I want to have DropDownListFor in MVC</p>
  
  <pre><code>@foreach (var item in Model)
  {
      @Html.DropDownListFor(modelItem =&gt; item.TitleIds, new SelectList(ViewBag.TitleNames as System.Collections.IEnumerable, "TitleId", "Title.TitleText"), "No: " + ViewBag.MagNo, new { id = "TitleIds" })   
  }
  </code></pre>
  
  <p>in Controller</p>
  
  <pre><code>public ActionResult ArticleList(int id)
  {
      ArticleWriter_ViewModel viewModel = new ArticleWriter_ViewModel();
      Func&lt;IQueryable&lt;NumberTitle&gt;, IOrderedQueryable&lt;NumberTitle&gt;&gt; orderByFunc = null;
      Expression&lt;Func&lt;NumberTitle, bool&gt;&gt; filterExpr = null;
      if (id &gt; 0)
      {
          filterExpr = p =&gt; p.MagazineId.Equals(id);
      }
      var wholeTitles = unitOfWork.NumberTitleRepository.Get(filterExpr,  orderByFunc, "Magazine,Title").ToList();          
  
      ViewBag.MagNo = wholeTitles[0].Magazine.MagNo.ToString();
      ViewBag.MagId = wholeTitles[0].Magazine.Id;
      ViewBag.TitleNames = wholeTitles;
  
      return View("../Panel/Magazine/ArticleList", "_BasicLayout", viewModel);
  }
  </code></pre>
  
  <p>but I get this error</p>
  
  <blockquote>
    <p>'<code>System.Web.Mvc.HtmlHelper&lt;System.Collections.Generic.IEnumerable&lt;Cinemavaadabiat.ViewModel.ArticleWriter_ViewModel&gt;&gt;</code>' has no applicable method named '<code>DropDownListFor</code>' but appears to have an extension method by that name. Extension methods cannot be dynamically dispatched. Consider casting the dynamic arguments or calling the extension method without the extension method syntax.</p>
  </blockquote>
  
  <p>I can't understand the error, what should I check for it?</p>