Question

I am working on an old project that has some user controls. On website one of these controls are being called like this:

<form id="frmDesignation" runat="server" >
  <table><tr><td>
    <sidenav:menu runat="server" ID="mymenu"></sidenav:menu>
  </td></tr></table>
</form>

At the top the user control has been registered:

<%@ Register TagName="menu" TagPrefix="sidenav" Src="~/Common_UC/Menu_Sidenav.ascx"%>

But I am getting

Error   543 Unknown server tag 'sidenav:menu'   

The user control is in right place, everything else seems fine. Am I missing something?

UPDATE:
As gbs mentioned in his comment, the problem was in my UC itself. It had some build error in itself so MAY BE that’s why I was getting the error message (I can’t test it now, don’t have the code 🙁 )

Answer 1

Mainly two things:

1: There is some issue with your UC itself.

2: You might want to try rebuilding the Project.