在Angular UI-router中继承嵌套视图的参数？

$stateProvider.state('parentState', {
  url: '/parent/:parentId',
  templateUrl: 'parent.html',
  controller: 'ParentController'
}).state('parentState.childState', {
  url: '/child/:childId',
  templateUrl: 'child.html',
  controller: 'ChildController'
});

app.controller('ChildController', ['$scope', '$stateParams', function($scope, $stateParams) {
  $scope.parentId = $stateParams.parentId;
  $scope.childId = $stateParams.childId;
}]);