Rock.Model.GroupService.GetNavigationChildren C# (CSharp) Method

        public IQueryable<Group> GetNavigationChildren( int id, int rootGroupId, bool limitToSecurityRoleGroups, List<int> groupTypeIncludedIds, List<int> groupTypeExcludedIds, bool includeInactiveGroups = true )
        {
            return this.GetChildren( id, rootGroupId, limitToSecurityRoleGroups, groupTypeIncludedIds, groupTypeExcludedIds, includeInactiveGroups, true );
        }

        public IQueryable<TreeViewItem> GetChildren( int id, int rootGroupId, bool limitToSecurityRoleGroups, string groupTypeIds )
        {
            var user = CurrentUser();
            if ( user != null )
            {
                var groupService = new GroupService();
                groupService.Repository.SetConfigurationValue( "ProxyCreationEnabled", "false" );
                var qry = groupService.GetNavigationChildren( id, rootGroupId, limitToSecurityRoleGroups, groupTypeIds );

                List<Group> groupList = new List<Group>();
                List<TreeViewItem> groupNameList = new List<TreeViewItem>();

                foreach ( var group in qry )
                {
                    if ( group.IsAuthorized( "View", user.Person ) )
                    {
                        groupList.Add( group );
                        var treeViewItem = new TreeViewItem();
                        treeViewItem.Id = group.Id.ToString();
                        treeViewItem.Name = System.Web.HttpUtility.HtmlEncode( group.Name );

                        // if there a IconCssClass is assigned, use that as the Icon.
                        var groupType = Rock.Web.Cache.GroupTypeCache.Read( group.GroupTypeId );
                        if ( groupType != null )
                        {
                            treeViewItem.IconCssClass = groupType.IconCssClass;
                        }

                        groupNameList.Add( treeViewItem );
                    }
                }

                // try to quickly figure out which items have Children
                List<int> resultIds = groupList.Select( a => a.Id ).ToList();

                var qryHasChildren = from x in Get().Select( a => a.ParentGroupId )
                                     where resultIds.Contains( x.Value )
                                     select x.Value;

                var qryHasChildrenList = qryHasChildren.ToList();

                foreach ( var g in groupNameList )
                {
                    int groupId = int.Parse( g.Id );
                    g.HasChildren = qryHasChildrenList.Any( a => a == groupId );
                }

                return groupNameList.AsQueryable();
            }
            else
            {
                throw new HttpResponseException( HttpStatusCode.Unauthorized );
            }
        }