myApp.factory('ModalService',['$modal',function($modal) {
    return {
        trigger: function(template) {
            $modal.open({
                templateUrl: template,size: 'lg',controller: function($scope,$modalInstance) {
                    $scope.ok = function() {
                        $modalInstance.close($scope.selected.item);
                    };
                    $scope.cancel = function() {
                        $modalInstance.dismiss('cancel');
                    };
                }
            });
        },close: function() {
            // this should close all modal instances
        }
    };
}]);

如何从控制器或任何其他模块调用ModalService.close()时关闭所有模态实例？