/// <summary>
 /// Конструктор по умолчанию.
 /// </summary>
 public FriendsViewModel(string uniqueKey, ulong userID)
     : base(uniqueKey)
 {
     _friends             = new FriendsCollection(userID);
     _friendsOnline       = new FriendsOnlineCollection(userID);
     _friendsList         = new FriendsListCollection(userID);
     RefreshCommand       = new RelayCommand(() => Friends.Refresh());
     RefreshOnlineCommand = new RelayCommand(() => FriendsOnline.Refresh());
     RefreshListCommand   = new RelayCommand(() => FriendsList.Refresh());
 }