The designer could not be shown for this file because none of the

I was working on converting an example pattern from C# to VB.NET for Page Controller in http://msdn.microsoft.com/library/de...esPatterns.asp (Web Service Patterns) when I ran into a nasty bug. I have not tried just setting up a project with their C# to see if it works. We are a VB shop and I'd like to make a case for using this pattern. But not if there is some weird sequence to get it to work.

1) I create a web app project.

2) I add a vb class file with this code:
Imports System
Imports System.Web.UI
Imports System.Web.UI.WebControls

Public Class BasePage
Inherits System.Web.UI.Page

End Class

3) I build the solution.

4) I go to the code behind page of WebForm1.aspx and change the Inherited class from System.Web.UI.Page to BasePage

5) I switch over to the designer page and I receive the following error:
The designer could not be shown for this file because none of the classes within it can be designed. The designer inspected the following classes in the file:

WebForm1 --- The base class 'PageController.BasePage' could not be loaded. Ensure the assembly has been referenced or built if it is part of the project.

Thanks!