In

<Extension()> _
Public Function [In](Of T)(ByVal Source As T, ByVal ParamArray List As T()) As Boolean
    For Each Value As T In List
        If Value.Equals(Source) Then
            Return True
        End If
    Next
    Return False
End Function

Dim IsAdmin as boolean = UserName.ToLower.In("admin","administrator", "sysop")