public virtual void UpdateContacts(Contact[] displayedContacts, Contact[] deletedContacts)
 {
     if (ContactGroup == null)
     {
         AddContactGroup();
     }
     ContactGroup.UpdateContacts(displayedContacts, deletedContacts);
 }
 public virtual void UpdateContacts(Contact[] contacts, Contact[] deletedContacts)
 {
     if (contacts == null)
     {
         return;
     }
     if (ContactGroup == null)
     {
         AddContactGroup();
     }
     ContactGroup.UpdateContacts(contacts, deletedContacts);
 }