public override void Init(object initData)
 {
     if (initData != null) {
         Contact = (Contact)initData;
     } else {
         Contact = new Contact ();
     }
 }
 public void UpdateContact (Contact contact)
 {
     if (contact.Id == 0)
     {
         contact.Id = _contacts.Count + 1;
         _contacts.Add(contact);
     }
     else
     {
         var oldContact = _contacts.Find(c => c.Id == contact.Id);
         oldContact.Name = contact.Name;
         oldContact.Phone = contact.Phone;
     }
 }