/// <summary>
        /// Активирует модель представления.
        /// </summary>
        public override async void Activate(NavigationMode mode = NavigationMode.New)
        {
            _retriesCount++;
            var response = await(new GetUsersRequest()).ExecuteAsync();

            if (response.Error.ErrorType == VKErrors.None)
            {
                Profile       = response.Response[0];
                _retriesCount = 0;
            }
            else if (_retriesCount <= 5)
            {
                Activate();
            }
            else
            {
                _retriesCount = 0;
            }
        }
        /// <summary>
        /// Конструктор по умолчанию.
        /// </summary>
        public SidebarViewModel()
        {
#if DEBUG
            if (IsInDesignModeStatic)
            {
                Profile = new VKProfileBase
                {
                    FirstName = "Роман",
                    LastName  = "Гладких",
                    Status    = "OneVK design mode."
                };
                MessagesCount = 159;
            }
#endif
            GoToMessagesView = new RelayCommand(() => NavigationHelper.Navigate(AppViews.MessagesView));

            ServiceHelper.VKLongPollService.MessagesCounterChanged += (s, e) =>
            {
                MessagesCount = e.Count;
                RaisePropertyChanged("HasNotifications");
            };
            Messenger.Default.Register <VKAccountGetCountersResponse>(this, OnCountersMessageReceived);
        }
 /// <summary>
 /// Деактивирует модель представления.
 /// </summary>
 public override void Deactivate(NavigationMode mode = NavigationMode.New)
 {
     Profile = null;
 }