Public Class MyServiceAuthorizationManager
    Inherits ServiceAuthorizationManager
    Protected Overrides Function CheckAccessCore(ByVal operationContext As OperationContext) As Boolean
        ' Extract the action URI from the OperationContext. Match this against the claims
        ' in the AuthorizationContext.
        Dim action As String = operationContext.RequestContext.RequestMessage.Headers.Action
        Console.WriteLine("action: {0}", action)

        ' Iterate through the various claim sets in the AuthorizationContext.
        For Each cs As ClaimSet In operationContext.ServiceSecurityContext.AuthorizationContext.ClaimSets
            ' Examine only those claim sets issued by System.
            If cs.Issuer Is ClaimSet.System Then
                ' Iterate through claims of type "http://example.org/claims/allowedoperation".
                For Each c As Claim In cs.FindClaims("http://example.org/claims/allowedoperation", Rights.PossessProperty)
                    ' Write the claim resource to the console.
                    Console.WriteLine("resource: {0}", c.Resource.ToString())

                    ' If the claim resource matches the action URI, then return true to allow access.
                    If action = c.Resource.ToString() Then
                        Return True
                    End If
                Next c
            End If
        Next cs

        ' If this point is reached, return false to deny access.
        Return False
    End Function
End Class