指令中的ng-options

Question

i want to use "ng-options" in a directive. First let me show you some code :

fooController.js

        init();
        function init () {
            $scope.randomOptions = [{id: '1', name: 'AAA'},
                                    {id: '2', name: 'BBB'},
                                    {id: '3', name: 'CCC'},
                                    {id: '4', name: 'DDD'},
                                    {id: '5', name: 'EEE'}];
        }

index.html

<div sort-container ng-model="fooBy" opts="randomOptions"></div>

foobarDirective.js

    foobarDirective = function() {

        return {
            restrict: 'A',
            templateUrl: '/templates/directives/foobarDirective.html',
            transclude: true,
            scope: {
                opts        : '='
            }
        };

    };

foobarDirective.html

<select ng-options="item.id as item.name for item in opts"></select>

<div ng-repeat="item in opts track by $index">
     %(item.id)% - %(item.name)%
</div>

So that's what I got so far. But ng-options is still not working, besides that I got some questions which might help me to understand directives further.

a) First I tried to deliver the object [$scope.randomOptions] via the opts-attribute in the DIV tag, but that didn't work. I would really prefer not to write an object into the parent.scope at all and just to paste it as option.

b) When I use

opts : '@'
instead of
opts : '='

I can remove the unneeded two-way-binding, but my object won't delivered in the right way. Does '@' also define my object as a string ?

Thanks for helping me out guys :)

Answer 1

ng-options only works with an accompanying ng-model (I assume the ng-repeat works?)

<select ng-model="selectedItem"
        ng-options="item.id as item.name for item in opts">

Two-way binding would indeed be a waste (unless you are planning to modify the options from within the directive). "@" is a one-way string binding.

One way you could create a one-way binding is to use "&" - this will create a function a result of which is the result of a bound expression. So, while it is somewhat unintuitive way to use "&" this will give you a one-way bound property:

<foobar opts="randomOptions"></foobar>

Then, inside the directive you would use like so:

<select ng-model="selectedItem"
        ng-options="item.id as item.name for item in opts()">

(notice the function at the end opts() )