Retrieving Value DataRowView In Combobox?

I have a problem in my code I can't seem to find a solution for.. One combobox is being filled up with a datatable like this:

CbUsers.Datasource = usersDAO.getUsers()

The getUsers() returns a datatable from my acces database. Users have a name and id, I want to use both of them but it should be something like this:

CbUsers.DisplayMember = "username"
CbUsers.valueMember = "userid"

In other words, I want to see the user name, but work with the user ID. So far the code worked, but it only displays stuff.

Now, in a method I want to use the id of the selected user in the combobox but that has been given me some trouble.

If I use this line I get a DataRowView: CbUsers.selectedValue

When I try to retrieve information from it, it throws an exception. I've tried lots of different code and it never worked..

If I put the DataRowView in a local variable and do this:
id = drv.items(0)

I only get exceptions..

way to work with a combobox that displays usernames but works with their id's?