I am using IsolatedStorageSettings to store a contact list for a key in my app. But the app only stores the list till the app is active(i.e. like navigating from one page to another). If I exit the app and again relaunch it, the stored key/contact list is not found. How do i permanently save a list for an app, till the app is installed? Here is the code of my viewmodel, I am using:
public class ContactsViewModel : ViewModelBase
{
private static IsolatedStorageSettings appSettings = IsolatedStorageSettings.ApplicationSettings;
private List<SavedContact> _SavedContactsList;
public ContactsViewModel()
{
Contacts cons = new Contacts();
cons.SearchAsync(String.Empty, FilterKind.None, null);
cons.SearchCompleted += new EventHandler<ContactsSearchEventArgs>(OnContactSearchCompleted);
SaveSavedContactsCommand = new RelayCommand(OnSaveSavedContacts);
}
private List<SavedContact> GetSavedContacts()
{
if (appSettings.Contains("SavedContacts"))
{
var savedContacts = (List<SavedContact>)appSettings["SavedContacts"];
return savedContacts;
}
else
{
return new List<SavedContact>();
}
}
public RelayCommand SaveSavedContactsCommand { get; set; }
private void OnSaveSavedContacts()
{
if (!SavedContactsList.Any(x => x.IsSelected == true))
{
MessageBox.Show("Please select some contacts and then click on Save button.");
}
else
{
var selectedSavedContacts = SavedContactsList.Where(x => x.IsSelected == true).ToList();
SavedContacts = selectedSavedContacts;
MessageBox.Show("Emergency contact list added successfully.");
App.RootFrame.GoBack();
}
}
void OnContactSearchCompleted(object sender, ContactsSearchEventArgs e)
{
try
{
SavedContactsList = new List<SavedContact>();
var allContacts = new List<Contact>(e.Results.Where(x => x.PhoneNumbers.Count() > 0).OrderBy(c => c.DisplayName));
// var savedContacts = GetSavedContacts();
var savedContacts = SavedContacts;
foreach (Contact contact in allContacts)
{
SavedContact SavedContact = new SavedContact() { Contact = contact };
if (savedContacts.Any(x => x.Contact.PhoneNumbers.ElementAt(0).PhoneNumber == contact.PhoneNumbers.ElementAt(0).PhoneNumber))
{
SavedContact.IsSelected = true;
}
else
{
SavedContact.IsSelected = false;
}
SavedContactsList.Add(SavedContact);
}
}
catch (System.Exception ex)
{
MessageBox.Show("Error in retrieving contacts : " + ex.Message);
}
}
[DataMember]
public List<SavedContact> SavedContactsList
{
get { return _SavedContactsList; }
set
{
_SavedContactsList = value;
RaisePropertyChanged("SavedContactsList");
}
}
private List<SavedContact> SavedContacts
{
get
{
if (appSettings.Contains("SavedContacts"))
{
var savedContacts = (List<SavedContact>)appSettings["SavedContacts"];
return savedContacts;
}
else
{
return new List<SavedContact>();
}
}
set
{
appSettings["SavedContacts"] = value;
}
}
}
And the class SavedContact is followings:
[DataContract]
public class SavedContact : INotifyPropertyChanged
{
public SavedContact() { }
private bool _isSelected;
private Contact _contact;
[DataMember]
public bool IsSelected
{
get
{
return _isSelected;
}
set
{
if (_isSelected != value)
{
_isSelected = value;
OnPropertyChanged("IsSelected");
}
}
}
[DataMember]
public Contact Contact
{
get
{
return _contact;
}
set
{
if (_contact != value)
{
_contact = value;
OnPropertyChanged("Contact");
}
}
}
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
}
Where the view model is bound to a <toolKit: LongListMultiSelector />. The functionality is like, I select some contacts from my longlist multiselector and save it in storage to reuse it later. But if I exit the app and restarts it , the savedContacts returns null. While I navigate other pages in my app, the savedContacts is getting printed.
If I save a list first time , on app relaunch GetSavedContacts() returns a new list.
The problem isn't related to IsolatedStorageSettings or your RelayCommand. Looking in more detail the problem is with serialization and de-serialization of the Contact object. If you update your implementation to something like the example below, you should be fine.
public class ContactsViewModel : ViewModelBase
{
private static IsolatedStorageSettings appSettings = IsolatedStorageSettings.ApplicationSettings;
private List<UserContact> _contactList;
public ContactsViewModel()
{
Contacts cons = new Contacts();
cons.SearchAsync(String.Empty, FilterKind.None, null);
cons.SearchCompleted += new EventHandler<ContactsSearchEventArgs>(OnContactSearchCompleted);
SaveSavedContactsCommand = new RelayCommand(OnSaveSavedContacts);
}
public RelayCommand SaveSavedContactsCommand { get; private set; }
private void OnSaveSavedContacts()
{
if (!Contacts.Any(x => x.IsSelected == true))
{
MessageBox.Show("Please select some contacts and then click on Save button.");
}
else
{
var selectedSavedContacts = Contacts.Where(x => x.IsSelected == true).Select(x => new SavedContact{ Name = x.Contact.DisplayName, PhoneNumber = x.Contact.PhoneNumbers.ElementAt(0).PhoneNumber}).ToList();
SavedContacts = selectedSavedContacts;
MessageBox.Show("Emergency contact list added successfully.");
App.RootFrame.GoBack();
}
}
void OnContactSearchCompleted(object sender, ContactsSearchEventArgs e)
{
try
{
Contacts = new List<UserContact>();
var allContacts = new List<Contact>(e.Results.Where(x => x.PhoneNumbers.Count() > 0).OrderBy(c => c.DisplayName));
foreach (Contact contact in allContacts)
{
UserContact SavedContact = new UserContact() { Contact = contact };
if (SavedContacts.Any(x => x.PhoneNumber == contact.PhoneNumbers.ElementAt(0).PhoneNumber))
{
SavedContact.IsSelected = true;
}
else
{
SavedContact.IsSelected = false;
}
Contacts.Add(SavedContact);
}
}
catch (System.Exception ex)
{
MessageBox.Show("Error in retrieving contacts : " + ex.Message);
}
}
[DataMember]
public List<UserContact> Contacts
{
get { return _contactList; }
set
{
_contactList = value;
RaisePropertyChanged("Contacts");
}
}
public List<SavedContact> SavedContacts
{
get
{
if (appSettings.Contains("SavedContacts"))
{
var savedContacts = (List<SavedContact>)IsolatedStorageSettings.ApplicationSettings["SavedContacts"];
return savedContacts;
}
else
{
return new List<SavedContact>();
}
}
set
{
if (value != null)
{
IsolatedStorageSettings.ApplicationSettings["SavedContacts"] = value;
IsolatedStorageSettings.ApplicationSettings.Save();
}
}
}
}
public class SavedContact
{
public string Name { get; set; }
public string PhoneNumber { get; set; }
}
[DataContract]
public class UserContact : INotifyPropertyChanged
{
public UserContact() { }
private bool _isSelected;
private Contact _contact;
[DataMember]
public bool IsSelected
{
get
{
return _isSelected;
}
set
{
if (_isSelected != value)
{
_isSelected = value;
OnPropertyChanged("IsSelected");
}
}
}
[DataMember]
public Contact Contact
{
get
{
return _contact;
}
set
{
if (_contact != value)
{
_contact = value;
OnPropertyChanged("Contact");
}
}
}
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
}