title: User Controls not working in Visual Studio 2015
body: <p>A user control that was working is no longer being picked up in the ASPX file.</p>
  
  <p>ASPX File</p>
  
  <pre><code>&lt;%@ Register TagPrefix="Uc1" TagName="ContactForm" Src="~/Controls/VFEmailForm.ascx"  %&gt;
  
  &lt;uc1:VFEmailForm ID="VFEmailForm" runat="server" /&gt;
  </code></pre>
  
  <p>It was working but now isn't. A green line appears under the uc1:VFEmailForm and when you type Uc intellisense doesn't show Uc1. It is as though the register statement does not work - well it obviously doesn't. This was all working prior to upgrading to Visual Studio 2015.</p>
  
  <p>I've shown part of my web.config file as ancient posts have suggested this may be the cause.</p>
  
  <p>Web.config </p>
  
  <pre><code>&lt;pages&gt;
    &lt;namespaces&gt;
      &lt;add namespace="System.Web.Optimization" /&gt;
    &lt;/namespaces&gt;
    &lt;controls&gt;
      &lt;add tagPrefix="webopt" assembly="Microsoft.AspNet.Web.Optimization.WebForms" namespace="Microsoft.AspNet.Web.Optimization.WebForms" /&gt;
      &lt;add tagPrefix="ajaxToolkit" assembly="AjaxControlToolkit" namespace="AjaxControlToolkit" /&gt;
    &lt;/controls&gt;
  &lt;/pages&gt;
  </code></pre>
  
  <p>If there is a guru out there who can fix this I would appreciate it.</p>