title: HttpPostedFileBase missing reference
body: <p>I'm getting an error on <code>HttpPostedFileBase</code>:</p>
  
  <blockquote>
    <p>The type or namespace name 'HttpPostedFileBase'could not be found(are you missing a using directive or an assembly reference?)</p>
  </blockquote>
  
  <p>I have already tried to use <code>using System.Web</code> but didn't work at all.</p>
  
  <p><strong>Edit #1</strong></p>
  
  <pre><code>public IActionResult Upload(HttpPostedFileBase file)
      {
  
          if (file.contentlength &gt; 0)
          {
              var filename = Path.GetFileName(file.filename);
              var path = Path.Combine(Server.mappath("~/app_data/uploads"), filename);
              file.saveas(path);
          }
  
          return RedirectToAction("index");
      }
  </code></pre>
  
  <p>I dont acctually have a reference folder <a href="https://i.stack.imgur.com/YvU7O.png" rel="noreferrer">No references folder</a></p>