protected override void OnNavigatedTo(NavigationEventArgs e)
 {
     history = new HistoriesViewModel();
     histories = history.getHistory();
     //listViewHistory.Items.Add(histories);
     try
     {
         if (histories != null)
         {
             foreach (var hist in histories)
             {
                 listViewHistory.Items.Add(hist.ID + " :Used :" + hist.USED_UNITS + " Remained " + hist.REMAINING_UNITS + " DATE: " + hist.DATE + "");
             }
         }
         else
         {
             messageBox("No history in the database");
         }
     }
     catch (Exception ex)
     {
         messageBox("error " + ex.Message);
     }
     base.OnNavigatedTo(e);
 }
 protected override void OnNavigatedTo(NavigationEventArgs e)
 {
     history = new HistoriesViewModel();
     histories = history.getHistory();
     //listViewHistory.Items.Add(histories);
     try
     {
         if (histories != null)
         {
             foreach (var hist in histories)
             {
                 listViewHistory.Items.Add("-Number of Appliances :" + hist.NUMBER + " appliance'(s) \n-Consumed Units :" 
                     + hist.USED_UNITS + " Units  \n-Remained units :" + hist.REMAINING_UNITS + " \n-Date :" + hist.DATE + "\n");
             }
         }
         else
         {
             messageBox("No history in the database");
         }
     }
     catch (Exception ex)
     {
         messageBox("error " + ex.Message);
     }
     base.OnNavigatedTo(e);
 }