Inheritance: LearnLanguages.Navigation.EventMessages.NavigationEventMessage, INavigationFailedEventMessage
        ///// <summary>
        ///// Navigation requested event message, for navigating to view models using convention over configuration.
        ///// EXPECTED FORMAT: [CoreText]ViewModel
        ///// EXPECTED FORMAT: QueryString[key=PropertyName, value=PropertyValueAsString] (not implemented yet)
        ///// </summary>
        ///// <param name="requestedViewModelCoreText">e.g. core = Login for LoginViewModel, core=AddNew for AddNewViewModel</param>
        ///// <param name="queryString"></param>
        //public NavigationFailedEventMessage(string requestedViewModelCoreText, Guid navigationId, string errorInfo)
        //  : base(requestedViewModelCoreText, navigationId)
        //{
        //  ErrorInfo = errorInfo;
        //}

        //public NavigationFailedEventMessage(string requestedViewModelCoreText,
        //                                    string query,
        //                                    Guid navigationId,
        //                                    string errorInfo)
        //  : base(requestedViewModelCoreText, query, navigationId)
        //{
        //}

        //public NavigationFailedEventMessage(string requestedViewModelCoreText,
        //                                    IDictionary<string, string> queryEntries,
        //                                    Guid navigationId)
        //  : base(requestedViewModelCoreText, queryEntries, navigationId)
        //{
        //}

        //public string ErrorInfo { get; private set; }

        public static void Publish(NavigationInfo navInfo)
        {
            var eventMsg = new NavigationFailedEventMessage(navInfo);

            Services.EventAggregator.Publish(eventMsg);
        }
    ///// <summary>
    ///// Navigation requested event message, for navigating to view models using convention over configuration.
    ///// EXPECTED FORMAT: [CoreText]ViewModel
    ///// EXPECTED FORMAT: QueryString[key=PropertyName, value=PropertyValueAsString] (not implemented yet)
    ///// </summary>
    ///// <param name="requestedViewModelCoreText">e.g. core = Login for LoginViewModel, core=AddNew for AddNewViewModel</param>
    ///// <param name="queryString"></param>
    //public NavigationFailedEventMessage(string requestedViewModelCoreText, Guid navigationId, string errorInfo)
    //  : base(requestedViewModelCoreText, navigationId)
    //{
    //  ErrorInfo = errorInfo;
    //}

    //public NavigationFailedEventMessage(string requestedViewModelCoreText, 
    //                                    string query, 
    //                                    Guid navigationId, 
    //                                    string errorInfo)
    //  : base(requestedViewModelCoreText, query, navigationId)
    //{
    //}

    //public NavigationFailedEventMessage(string requestedViewModelCoreText, 
    //                                    IDictionary<string, string> queryEntries,
    //                                    Guid navigationId)
    //  : base(requestedViewModelCoreText, queryEntries, navigationId)
    //{
    //}

    //public string ErrorInfo { get; private set; }

    public static void Publish(NavigationInfo navInfo)
    {
      var eventMsg = new NavigationFailedEventMessage(navInfo);
      Services.EventAggregator.Publish(eventMsg);
    }