/// <summary>
        /// Populates the page with content passed during navigation.  Any saved state is also
        /// provided when recreating a page from a prior session.
        /// </summary>
        /// <param name="navigationParameter">The parameter value passed to
        /// <see cref="Frame.Navigate(Type, Object)"/> when this page was initially requested.
        /// </param>
        /// <param name="pageState">A dictionary of state preserved by this page during an earlier
        /// session.  This will be null the first time a page is visited.</param>
        private async void navigationHelper_LoadState(object sender, LoadStateEventArgs e)
        {
            _queryText = e.NavigationParameter as String;

            // Fetch the serach results from JobsDataSource
            var searchResults = await JobDataSource.SearchJobsBySearchTextAsync(_queryText);

            // Add the counts for various job status
            int countOnSite     = searchResults.Count(item => item.Status == "On Site");
            int countNotStarted = searchResults.Count(item => item.Status == "Not Started");
            int countCompleted  = searchResults.Count(item => item.Status == "Completed");

            // Add the filters based upon the job status
            var filterList = new List <Filter>();

            filterList.Add(new Filter("All", searchResults.Count, true));
            if (countOnSite > 0)
            {
                filterList.Add(new Filter("On Site", countOnSite, false));
            }
            if (countNotStarted > 0)
            {
                filterList.Add(new Filter("Not Started", countNotStarted, false));
            }
            if (countCompleted > 0)
            {
                filterList.Add(new Filter("Completed", countCompleted, false));
            }

            // Communicate results through the view model
            this.DefaultViewModel["QueryText"]   = " " + '\u201c' + _queryText + '\u201d';
            this.DefaultViewModel["Filters"]     = filterList;
            this.DefaultViewModel["ShowFilters"] = filterList.Count > 0;
            this.DefaultViewModel["Results"]     = searchResults;
        }
        /// <summary>
        /// Invoked when a filter is selected using a RadioButton when not snapped.
        /// </summary>
        /// <param name="sender">The selected RadioButton instance.</param>
        /// <param name="e">Event data describing how the RadioButton was selected.</param>
        async void Filter_Checked(object sender, RoutedEventArgs e)
        {
            var filter = (sender as FrameworkElement).DataContext;

            // Mirror the change into the CollectionViewSource.
            // This is most likely not needed.
            if (filtersViewSource.View != null)
            {
                filtersViewSource.View.MoveCurrentTo(filter);
            }

            // Determine what filter was selected
            var selectedFilter = filter as Filter;

            if (selectedFilter != null)
            {
                // Mirror the results into the corresponding Filter object to allow the
                // RadioButton representation used when not snapped to reflect the change
                selectedFilter.Active = true;

                // Load the search results and filter them based on user-selected filter value
                _searchResults = await JobDataSource.SearchJobsBySearchTextAsync(_queryText);

                _searchResults = (selectedFilter.Name.Equals("All")) ? _searchResults :
                                 new List <Job>(_searchResults.Where(job => job.Status.Equals(selectedFilter.Name)).ToList());
                this.DefaultViewModel["Results"] = _searchResults;

                // Ensure results are found
                object      results;
                ICollection resultsCollection;
                if (this.DefaultViewModel.TryGetValue("Results", out results) &&
                    (resultsCollection = results as ICollection) != null &&
                    resultsCollection.Count != 0)
                {
                    VisualStateManager.GoToState(this, "ResultsFound", true);
                    return;
                }
            }

            // Display informational text when there are no search results.
            this.DefaultViewModel["ShowFilters"] = false;
            VisualStateManager.GoToState(this, "NoResultsFound", true);
        }