Accessing a value in a .master page from a class

Hello All,

I am trying to access the value of a dropdown list that is in my .master page from a function.  

I've found some instruction which gets me close (I hope).  The only piece that gives me trouble is specifying the master page to use -- "Page.Master" or "Me.Master" doesn't work since I'm this function does not reside in a nested page.  The message I get now (about Page.Master) is: "Reference to a non-shared member requires an object reference".

How can I resolve this so that I am able to get the dropdowns selected item?  Thanks in advance.

Here is the code on my .master.vb page:

Public Property IdentityText() As String
Get
Return AlternateID.SelectedValue
End Get
End Property

This is from my function (securityaccess.vb):

Dim Master As MasterPage = Page.Master
Dim Dropdown As DropDownList = master.FindControl("AlternateID")
Dim ID As String = Dropdown.SelectedValue.ToString