Index: branches/5.2.x/core/units/helpers/list_helper.php
===================================================================
diff -u -N -r14628 -r14646
--- branches/5.2.x/core/units/helpers/list_helper.php	(.../list_helper.php)	(revision 14628)
+++ branches/5.2.x/core/units/helpers/list_helper.php	(.../list_helper.php)	(revision 14646)
@@ -33,7 +33,7 @@
 			$sort_fields = is_array($sorting) ? array_keys($sorting) : Array ();
 
 			for ($order_number = 0; $order_number < 2; $order_number++) {
-				// currect sorting in list
+				// current sorting in list
 				$sorting_pos = $user_sorting_start + $order_number;
 				$current_order_field = $list->GetOrderField($sorting_pos, true);
 				$current_order_direction = $list->GetOrderDirection($sorting_pos, true);
@@ -120,6 +120,82 @@
 			if ( $forced_sorting = getArrayValue($list_sortings, $sorting_prefix, 'ForcedSorting') ) {
 				$user_sorting_start = count($forced_sorting);
 			}
+
 			return $user_sorting_start;
 		}
+
+		/**
+		 * Returns ID of previous/next record related to current record
+		 *
+		 * @param kDBItem $object
+		 * @param string $list_prefix
+		 * @param bool $next
+		 * @return int
+		 */
+		function getNavigationResource(&$object, $list_prefix, $next = true, $select_fields = null)
+		{
+			$list =& $this->Application->recallObject($list_prefix);
+			/* @var $list kDBList */
+
+			if ( !isset($select_fields) ) {
+				$select_fields = '%1$s.' . $object->IDField;
+			}
+
+			if ( is_array($select_fields) ) {
+				$select_fields = implode(', ', $select_fields);
+			}
+
+			$list->SetSelectSQL( str_replace(Array ('%1$s.*', '%2$s'), Array ($select_fields, ''), $list->GetPlainSelectSQL()) );
+
+			$operators = Array (
+				'asc' => $next ? '>' : '<',
+				'desc' => $next ? '<' : '>',
+			);
+
+			$where_clause = Array ();
+			$lang = $this->Application->GetVar('m_lang');
+			$order_fields = $order_fields_backup = $list->getOrderFields();
+
+			foreach ($order_fields as $index => $order) {
+				$where_clause[$index] = Array ();
+
+				if ( !$next ) {
+					$list->changeOrderDirection($index, $order_fields_backup[$index][1] == 'asc' ? 'desc' : 'asc');
+				}
+
+				for ($i = 0; $i <= $index; $i++) {
+					$order_field = $order_fields_backup[$i][0];
+					$is_expression = $order_fields_backup[$i][2];
+
+					if ( preg_match('/^IF\(COALESCE\(.*?\.(l' . $lang . '_.*?), ""\),/', $order_field, $regs) ) {
+						// undo result of kDBList::getMLSortField method
+						$order_field = $regs[1];
+						$is_expression = false;
+					}
+
+					$order_direction = $order_fields_backup[$i][1];
+
+					$field_prefix = $list->isVirtualField($order_field) || $is_expression ? '' : '%1$s.';
+
+					$actual_operator = $i == $index ? $operators[$order_direction] : '=';
+					$where_clause[$index][] = $field_prefix . $order_field . ' ' . $actual_operator . ' ' . $this->Conn->qstr($object->GetDBField($order_field));
+				}
+
+				$where_clause[$index] = '(' . implode(') AND (', $where_clause[$index]) . ')';
+			}
+
+			$where_clause = '(%1$s.' . $object->IDField . ' != ' . $object->GetID() . ') AND ((' . implode(') OR (', $where_clause) . '))';
+			$list->addFilter('navigation_filter', $where_clause);
+
+			$sql = $list->extractCalculatedFields($list->GetSelectSQL());
+
+			$list->removeFilter('navigation_filter');
+			$list->setOrderFields($order_fields_backup);
+
+			if ( $this->Application->isDebugMode() ) {
+				$this->Application->Debugger->appendHTML('Quering <strong>' . ($next ? 'next' : 'previous') . '</strong> item for "<strong>' . $list_prefix . '</strong>" list:');
+			}
+
+			return $this->Conn->GetOne($sql);
+		}
 	}
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