/// <summary>
        /// Methode à exécuter lors du clic sur la commande Accueil
        /// </summary>
        public async void ExecuteModifier()
        {
            try{

             // Create the message dialog and set its content and title
                var messageDialog = new MessageDialog("Êtes-vous certain de vouloir modifier le calendrier selectionné ?", "Demande de confirmation");

                // Add commands and set their command ids
                messageDialog.Commands.Add(new UICommand("Annuler", null, 0));
                messageDialog.Commands.Add(new UICommand("Confirmer", null, 1));

                // Set the command that will be invoked by default
                messageDialog.DefaultCommandIndex = 0;

                // Show the message dialog and get the event that was invoked via the async operator
                var commandChosen = await messageDialog.ShowAsync();

                if (commandChosen.Label.Equals("Confirmer"))
                {
                    CalendarControler controler = new CalendarControler();
                    await controler.UpdateCalendar(cal.Calendar);
                   
                   
                   //on met à jour la liste des calendriers
                    parent.MajCalendar(cal.Calendar);

                }
            }
            catch (HttpRequestException e)
            {
                var messageDialog = new MessageDialog(e.Message+"Impossible de modifier le calendrier. Vous n'êtes plus connecté à votre compte.", "Suppression impossible");
                messageDialog.ShowAsync();
            }
        }
        /// <summary>
        /// Methode à exécuter lors du clic sur la commande Accueil
        /// </summary>
        public async void ExecuteModifier()
        {
            try
            {

                // Create the message dialog and set its content and title
                var messageDialog = new MessageDialog(IConstantes.MSG_CONFIRM_UPDATE_CAL);

                // Add commands and set their command ids
                messageDialog.Commands.Add(new UICommand(IConstantes.BUTTON_CANCEL, null, 0));
                messageDialog.Commands.Add(new UICommand(IConstantes.BUTTON_CONFIRM, null, 1));

                // Set the command that will be invoked by default
                messageDialog.DefaultCommandIndex = 0;

                // Show the message dialog and get the event that was invoked via the async operator
                var commandChosen = await messageDialog.ShowAsync();

                if (commandChosen.Label.Equals(IConstantes.BUTTON_CONFIRM))
                {
                    CalendarControler controler = new CalendarControler();
                    await controler.UpdateCalendar(cal.Calendar);


                    //on met à jour la liste des calendriers
                    parent.MajCalendar(cal.Calendar);

                }
            }
            catch (HttpRequestException e)
            {
                var messageDialog = new MessageDialog(e.Message + IConstantes.EXCEPTION_MSG_UPDATE);
                messageDialog.ShowAsync();
            }
        }