private async void createUser()
        {
            if (await fieldsOK())
            {
                User user = new User();
                
                user.Date_of_birth = null;
                user.Diplomas = Diplomas;
                user.Email = Email;
                user.Firstname = Firstname;
                user.Jobs = Jobs;
                user.Lastname = Lastname;
                user.Living_city_id = SelectedVille.City_id;

                user.password = encrypt(Password);

                user.Phone_number = Phone_Number;
                user.Street_name = Street_name;
                user.Street_number = Street_number;
                user.User_id = await dataAccess.getNewUserId();

                if(await dataAccess.setNewUserAsync(user))
                {
                    new MessageDialog(ResourceManager.Current.MainResourceMap.GetValue("Resources/Account_successfully_created").ValueAsString).ShowAsync();
                    _navigationService.NavigateTo("Iden");
                }
                else
                {
                    new MessageDialog(ResourceManager.Current.MainResourceMap.GetValue("Resources/An_error_occurred_during_account_creation").ValueAsString).ShowAsync();
                }
            }
        }
        public async Task<bool> setNewUserAsync(User user)
        {
            HttpClient client = new HttpClient();

            var values = new Dictionary<string, string>
            {

               { "User_id", Convert.ToString(user.User_id, CultureInfo.InvariantCulture) },
               { "Date_of_birth",  null},
               { "Diplomas", user.Diplomas },
               { "Email", user.Email },
               { "Firstname", user.Firstname},
               { "Jobs", user.Jobs },
               { "Lastname", user.Lastname},
               { "Phone_number", user.Phone_number },
               { "Street_name", user.Street_name},
               { "Street_number", user.Street_number },
               { "Living_city_id", Convert.ToString(user.Living_city_id, CultureInfo.InvariantCulture) },
               { "password", user.password}
            };

            var content = new FormUrlEncodedContent(values);

            var response = await client.PostAsync("http://helpngowebapi.azurewebsites.net/api/users", content);

            return response.IsSuccessStatusCode;
        }