title: None of my Extension Methods are showing in Code behind
body: <p>I have a number of extension methods defined in my current project. It is a VB.NET project. I have no problem using these methods inside files that are in the App_Code directory, this is the same place that I defined the methods. However, in my page.aspx.vb code behind page these methods are not showing up. I have tried including the correct namespace, with no luck.</p>
  
  <p>Does anyone have an idea as to why I can't call an extension method in a code behind file?</p>
  
  <p>Defined in the App_Code folder</p>
  
  <pre><code>&lt;Extension()&gt; _
  Public Function GetSelected(ByVal apps As List(Of Appointment)) As Appointment
      Dim selected = From a In apps _
                     Where a.Selected = True
  
      Return selected.Single
  End Function
  </code></pre>
  
  <p>Defined in the App_Code folder, inside another class(this one works just fine)</p>
  
  <pre><code>Public ReadOnly Property Selected() As Appointment
      Get
          Return _appointments.GetSelected()
      End Get
  End Property
  </code></pre>
  
  <p>Defined in the App Root folder, inside a code behind file(Not working)</p>
  
  <pre><code>Public ReadOnly Property Selected() As Appointment
      Get
          Return _appointments.GetSelected()
      End Get
  End Property
  </code></pre>
  
  <p>They are all in the same application, no external references. And When I build the project there are no errors, until I try to use the extension method in the code behind. At that point the error is 'GetSelected' is not a member of 'System.Collections.Generic.List(Of Appointment)'</p>