title: TFS website build error
body: <p>I have a problem using TFS to build a website, it's not a .NET project but an old website, without a csproj file, just the web.config file.</p>
  
  <p>In the web.config file, is referenced the "System.Web.Extensions" dll like this in system.web key :</p>
  
  <pre><code>&lt;compilation debug="true"&gt;
    &lt;assemblies&gt;
      &lt;add assembly="System.DirectoryServices, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/&gt;
      &lt;add assembly="System.Messaging, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/&gt;
      &lt;add assembly="System.Windows.Forms, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/&gt;
      &lt;add assembly="System.Configuration.Install, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/&gt;
      &lt;add assembly="System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/&gt;
      &lt;add assembly="System.Data, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/&gt;
      &lt;add assembly="System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/&gt;
      &lt;add assembly="System.Xml, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/&gt;
      &lt;add assembly="System.EnterpriseServices, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/&gt;
      &lt;add assembly="System.Configuration, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/&gt;
      &lt;add assembly="System.Drawing, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/&gt;
      &lt;add assembly="System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/&gt;
      &lt;add assembly="System.Web.Services, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/&gt;
      &lt;add assembly="System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/&gt;
      &lt;add assembly="System.Xml.Linq, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/&gt;
      &lt;add assembly="System.Data.DataSetExtensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/&gt;
      &lt;add assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/&gt;
    &lt;/assemblies&gt;
  </code></pre>
  
  <p>and a tag prefix is declared like this also in system.web key :</p>
  
  <pre><code>&lt;pages validateRequest="false"&gt;
    &lt;controls&gt;
      &lt;add tagPrefix="asp" namespace="System.Web.UI" assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/&gt;
      &lt;add tagPrefix="asp" namespace="System.Web.UI.WebControls" assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/&gt;
    &lt;/controls&gt;
  &lt;/pages&gt;
  </code></pre>
  
  <p>In the code, this tag prefix is used as this :</p>
  
  <pre><code>ASP.xxx_controls_customcontrol1_ascx userControl = ctrl as ASP.xxx_controls_customcontrol1_ascx;
  </code></pre>
  
  <p>The TFS build of the solution containing this web site fails with this error :</p>
  
  <pre><code>##[error]XXX\XXX\XXXXXX\Controls\uicCustomControl1.ascx.cs(93,0): Error CS0234: The type or namespace name 'xxx_controls_customcontrol1_ascx' does not exist in the namespace 'ASP' (are you missing an assembly reference?)
  </code></pre>
  
  <p><em>I added the System.Web.Extensions.dll file in the bin folder and I checkin this file in the TFS, but I still have this error.</em></p>
  
  <p>Any help ?</p>
  
  <p>Thank you.</p>