Bind to navigation properties

Question

I warking with EF 4 in vs 2010 with asp.net application.

In my page I put detailsview which connet to objectdatasource.

I want to bind navigate property to text in murkup like this:

'> according to this article (from o'reilly book)

Using the Entity Framework in n-Tier ASP.NET Applications which write by julie lerman in section "Example 21.10. A TemplateField, which can be used for navigation properties".

When I run the application I get a Compilation Error "The name 'Databinder' does not exist in the current context" someone can tell me what my mistake?

Thanks.