refresh token em vb net

Private Function DoAuthentication(ByRef rStrToken As String, ByRef rParameters As OAuth2Parameters) As Boolean

    Dim credential As UserCredential

    Dim Secrets = New ClientSecrets() With {

        .ClientId = m_strClientID,

        .ClientSecret = m_strClientSecret

    }

    ‘m_Scopes.Add(CalendarService.Scope.Calendar)

    m_Scopes.Add(“https://www.googleapis.com/auth/calendar https://www.google.com/m8/feeds/ https://mail.google.com/”)

    Try

        credential = GoogleWebAuthorizationBroker.AuthorizeAsync(Secrets, m_Scopes,

                                                                 “user”, CancellationToken.None,

                                                                 New FileDataStore(“PublicTalkSoftware.Calendar.Application”)).Result()
        ‘ Create the calendar service using an initializer instance

        Dim initializer As New BaseClientService.Initializer() With {

            .HttpClientInitializer = credential,

            .ApplicationName = “~~~~~~~~~~”

        }

        m_Service = New CalendarService(initializer)
        rStrToken = credential.Token.AccessToken.ToString()

        rParameters.AccessToken = credential.Token.AccessToken

        rParameters.RefreshToken = credential.Token.RefreshToken

    Catch ex As Exception

        ‘ We encountered some kind of problem, perhaps they have not yet authenticated?

        Return False

    End Try
    Return True

End Function