master-pages - 母版页不显示 IPrincipal 上的扩展方法

Question

我有一个问题，我找不到解决方案。

我有一个带有 IPrincipal 扩展方法的模块：

<System.Runtime.CompilerServices.Extension()> _
Public Function CanCallGhostbusters(ByRef activeUser As IPrincipal) As Boolean
    Dim result As Boolean = False

    resultado = activeUser.IsInRole("GB\GhostBustersCaller") AndAlso ...

    Return result
End Function

该代码在 .aspx 页面中运行良好：

Protected Sub Page_Load(ByVal s As Object, ByVal e As System.EventArgs) Handles Me.Load
    If User.CanCallGhostbusters Then
        //It works; cool!
    End If
End Sub

但它在母版页中不起作用；扩展方法不会出现在智能感知中。我努力了：

If HttpContext.Current.User.CanCallGhostbusters  Then
    //Error: CanCallGhostbusters is not a member of System.Security.Principal.IPrincipal
End If

Dim activeUser As System.Security.Principal.IPrincipal = HttpContext.Current.User
If activeUser.CanCallGhostbusters Then
    //Error: CanCallGhostbusters is not a member of System.Security.Principal.IPrincipal
End If

任何想法？

谢谢！