Rock.Model.PrayerRequestService.GetByCategoryIds C# (CSharp) Method

        public IEnumerable<PrayerRequest> GetByCategoryIds( List<int> categoryIds, bool onlyApproved = true, bool onlyUnexpired = true )
        {
            PrayerRequest prayerRequest = new PrayerRequest();
            Type type = prayerRequest.GetType();

            var prayerRequestEntityTypeId = Rock.Web.Cache.EntityTypeCache.GetId( type );

            // Get all PrayerRequest category Ids that are the **parent or child** of the given categoryIds.
            CategoryService categoryService = new CategoryService( (RockContext)Context );
            IEnumerable<int> expandedCategoryIds = categoryService.GetByEntityTypeId( prayerRequestEntityTypeId )
                .Where( c => categoryIds.Contains( c.Id ) || categoryIds.Contains( c.ParentCategoryId ?? -1 ) )
                .Select( a => a.Id );

            // Now find the active PrayerRequests that have any of those category Ids.
            var list = Queryable( "RequestedByPersonAlias.Person" ).Where( p => p.IsActive == true && expandedCategoryIds.Contains( p.CategoryId ?? -1 ) );

            if ( onlyApproved )
            {
                list = list.Where( p => p.IsApproved == true );
            }

            if ( onlyUnexpired )
            {
                list = list.Where( p => RockDateTime.Today <= p.ExpirationDate );
            }

            return list;
        }

        /// <summary>
        /// Finds all approved prayer requests for the given selected categories and orders them by least prayed-for.
        /// Also updates the prayer count for the first item in the list.
        /// </summary>
        /// <param name="categoriesList"></param>
        private void SetAndDisplayPrayerRequests( RockCheckBoxList categoriesList )
        {
            RockContext rockContext = new RockContext();
            PrayerRequestService service = new PrayerRequestService( rockContext );
            var prayerRequests = service.GetByCategoryIds( categoriesList.SelectedValuesAsInt ).OrderByDescending( p => p.IsUrgent ).ThenBy( p => p.PrayerCount );
            List<int> list = prayerRequests.Select( p => p.Id ).ToList<int>();

            Session[_sessionKey] = list;
            if ( list.Count > 0 )
            {
                UpdateSessionCountLabel( 1, list.Count );
                hfPrayerIndex.Value = "0";
                PrayerRequest request = prayerRequests.First();
                ShowPrayerRequest( request, rockContext );
            }
        }