private void UseGoogleCalendar() { UserCredential credential; using (var stream = new FileStream("credentials.json", FileMode.Open, FileAccess.Read)) { // The file token.json stores the user's access and refresh tokens, and is created // automatically when the authorization flow completes for the first time. string credPath = "token.json"; credential = GoogleWebAuthorizationBroker.AuthorizeAsync( GoogleClientSecrets.Load(stream).Secrets, Scopes, "user", CancellationToken.None, new FileDataStore(credPath, true)).Result; Console.WriteLine("Credential file saved to: " + credPath); } // Create Google Calendar API service. var service = new CalendarService(new BaseClientService.Initializer() { HttpClientInitializer = credential, ApplicationName = ApplicationName, }); var calendarRepository = new CalendarRepository(service); calendarRepository.EventInsert("Hello", DateTime.Now); }