public async override void OnNavigatedTo(object navigationParameter, Windows.UI.Xaml.Navigation.NavigationMode navigationMode, Dictionary<string, object> viewModelState) {
base.OnNavigatedTo(navigationParameter, navigationMode, viewModelState);
// Note: Each time app selects from main page (PhoneCallListPage) detail page (PhoneCallDetailPage) is recreated.
// Meaning that constructor is run and SelectedPhoneCall is null.
// If SuspendAndTerminate (e.g. debug mode) SelectedPhoneCall is saved to SessionState (because of [RestorableState] attribute).
// Therefore, if SelectedPhoneCall has been saved, use it instead of doing GetPhoneCallAsync.
if (SelectedPhoneCall == null) {
string errorMessage = string.Empty;
int phoneCallId = (int)navigationParameter;
if (phoneCallId == 0) {
SelectedPhoneCall = new PhoneCall();
SelectedPhoneCall.ValidateProperties();
RunAllCanExecute();
}
else {
try {
LoadingData = true;
CrudResult = await _phoneCallRepository.GetPhoneCallAsync(phoneCallId);
SelectedPhoneCall = JsonConvert.DeserializeObject<List<PhoneCall>>(CrudResult.Content.ToString()).FirstOrDefault<PhoneCall>();
}
catch (HttpRequestException ex) {
ErrorMessageTitle = ErrorMessagesHelper.HttpRequestExceptionError;
//TODO: Log stack trace to database here
ErrorMessage = string.Format("{0}", ex.Message);
}
finally {
LoadingData = false;
}
if (ErrorMessage != null && ErrorMessage != string.Empty) {
MessageDialog messageDialog = new MessageDialog(ErrorMessage, ErrorMessageTitle);
await messageDialog.ShowAsync();
_navService.GoBack();
}
}
}
RunAllCanExecute();
}
// When New button is pressed
private void OnNewPhoneCall() {
SelectedPhoneCall = new PhoneCall();
SelectedPhoneCall.ValidateProperties();
RunAllCanExecute();
}