private async void NavigationHelper_LoadState(object sender, LoadStateEventArgs e)
        {
            try
            {
                await StatusBar.GetForCurrentView().HideAsync();

                LoadingControl.DisplayLoadingError(false);
                LoadingControl.SetLoadingStatus(true);

                Supermarkets = (List <Supermarkt>) await GetSAData.GetAllSupermarkets();

                IList <Supermarkt> AanwezigeSupermarkten = null;

                try
                {
                    AanwezigeSupermarkten = await GetSAData.GetSelectedSuperMarkets();
                }
                catch
                {
                }

                if (AanwezigeSupermarkten != null && Supermarkets != null)
                {
                    NextButton.IsEnabled = true;

                    foreach (Supermarkt SA in Supermarkets)
                    {
                        foreach (Supermarkt SB in AanwezigeSupermarkten)
                        {
                            if (SB.Name == SA.Name)
                            {
                                SA.SupermarketEnabled = true;
                            }
                        }
                    }
                }
                else if (Supermarkets == null)
                {
                    throw new NullReferenceException();
                }

                SupermarktetsListview.ItemsSource = Supermarkets;
                ContentGrid.Visibility            = Visibility.Visible;
                LoadingControl.SetLoadingStatus(false);
            }
            catch
            {
                LoadingControl.SetLoadingStatus(false);
                LoadingControl.DisplayLoadingError(true);
            }
        }
        public List <Supermarkt> GetActiveSupermarkets()
        {
            if (this.ActiveSupermarkets != null)
            {
                return(ActiveSupermarkets);
            }

            this.ActiveSupermarkets = new List <Supermarkt>();
            List <Supermarkt> SupermarketsFromDatabase = base.GetObjectsByChildObjectID(DeletedField, 0, 0, OrderBy.ASC, NameField).Cast <Supermarkt>().ToList();
            List <Supermarkt> SupermarketsFromWeb      = (List <Supermarkt>)GetSAData.GetAllSupermarkets();

            for (int i = 0; i < SupermarketsFromWeb.Count; i++)
            {
                foreach (Supermarkt s in SupermarketsFromDatabase)
                {
                    if (s.URL == SupermarketsFromWeb[i].URL)
                    {
                        SupermarketsFromWeb.RemoveAt(i);
                        SupermarketsFromDatabase.Remove(s);
                        this.ActiveSupermarkets.Add(s);
                        i--;
                        break;
                    }
                }
            }

            foreach (Supermarkt s in SupermarketsFromDatabase)
            {
                s.Deleted = true;
                UpdateObject(s);
            }

            foreach (Supermarkt s in SupermarketsFromWeb)
            {
                AddObject(s);
                this.ActiveSupermarkets.Add(s);
            }

            return(ActiveSupermarkets);
        }