/// <summary>
        /// Methode, die aufgerufen wird, wenn das Fenster geladen wurde.
        /// Stellt die Serververbindungen her.
        /// </summary>
        /// <param name="o"></param>
        private void OnWindowLoaded(object o)
        {
            try
            {
                var restUrl = ConfigurationManager.AppSettings.Get("RestServerURL");
                var messageUrl = ConfigurationManager.AppSettings.Get("MessageServerURL");

                ClientSession.Instance.RelaxoClient = new RelaxoClient(restUrl);

                var client = new MessagingClient();
                client.Connect(messageUrl);
                ClientSession.Instance.MessageClient = client;
            }
            catch (Exception e)
            {
                ErrorMessage = e.Message;
                Debug.WriteLine(e.Message);
                Debug.WriteLine(e.StackTrace);
            }
        }