Using System.Data.Linq in a Razor view

You need to import the namespace into your view by adding @using System.Data.Linq at the top of your view. However if you want it in all your views then you need to add <add namespace="System.Data.Linq" /> to the web.config in your Views folder:

  <system.web.webPages.razor>
    <host factoryType="System.Web.Mvc.MvcWebRazorHostFactory, System.Web.Mvc, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
    <pages pageBaseType="System.Web.Mvc.WebViewPage">
      <namespaces>
        <add namespace="System.Web.Mvc" />
        <add namespace="System.Web.Mvc.Ajax" />
        <add namespace="System.Web.Mvc.Html" />
        <add namespace="System.Web.Routing" />
        <add namespace="System.Data.Linq" />
      </namespaces>
    </pages>
  </system.web.webPages.razor>

Although not relevent to your question you should really try to move this logic out of the view and into the controller, it will make things much easier to debug and means that your presentation is separated from your business logic.

What fixed it for me was to right click the System.Data.Linq assembly reference, then hit properties. In there set Copy Local to true.