public async void LoadCustomerArchive()
        {
            var customerArchive = await PersistencyServiceCustomerArchive.LoadCustomerArchiveFromJsonAsync();

            CustomerArchive.Clear();
            if (customerArchive != null)
            {
                foreach (var customer in customerArchive)
                {
                    CustomerArchive.Add(customer);
                }
            }
            else
            {
                CustomerArchive.Add(new Customer("Google", "12345678", "Nygade 12", "*****@*****.**", "Søren", "583567347648"));
            }
        }
 public void AddCustomer(Customer customer)
 {
     CustomerArchive.Add(customer);
     PersistencyServiceCustomerArchive.SaveCustomerArchiveAsJsonAsync(CustomerArchive);
 }
 public void RemoveCustomer(Customer customerToBeRemoved)
 {
     CustomerArchive.Remove(customerToBeRemoved);
     PersistencyServiceCustomerArchive.SaveCustomerArchiveAsJsonAsync(CustomerArchive);
 }
 public void AddCustomer(string companyName, string phoneNumber, string adress, string email, string att, string cvr)
 {
     CustomerArchive.Add(new Customer(companyName, phoneNumber, adress, email, att, cvr));
     PersistencyServiceCustomerArchive.SaveCustomerArchiveAsJsonAsync(CustomerArchive);
 }