Select the blank option of select box programmatically in AngularJS directive

问题

I have a select box with a blank option and some other options. The options are not generated with ngOptions directive, because they are generated on server side (with Symfony forms).

In some cases I want to unselect the selected value of the select box. So that the blank option is selected. But I cannot get this to work. The select box does not get updated.

I have created a jsfiddle to show the problem.

html

<div ng-controller="MyCtrl">
    <form name="form">
        <select ng-model="foo.hero" name="foo[hero]" my-directive="">
            <option value=""></option>
            <option value="1">Batman</option>
            <option value="2">Superman</option>
            <option value="3">Spiderman</option>
        </select>
    </form>
    <p>Selected: {{ foo.hero }}</p>
</div>

javascript

var myApp = angular.module('myApp',[]);

function MyCtrl($scope) {
    $scope.foo = {hero: '2'};
}

myApp.directive('myDirective', function($timeout) {
    return {
        require: ['ngModel', '?form'],
        link: function(scope, element, attrs, ctlrs) {
            $timeout(function() {
                var modelController = ctlrs[0];
                modelController.$setViewValue('');
            });
        }
    };
});

回答1:

Use modelController.$render() after you call $setViewValue. This will update the DOM element(s).

myApp.directive('myDirective', function($timeout) {
    return {
        require: ['ngModel', '?form'],
        link: function(scope, element, attrs, ctlrs) {
            $timeout(function() {
                var modelController = ctlrs[0];
                modelController.$setViewValue('');
                modelController.$render();
            });
        }
    };
});

Updated fiddle here.

回答2:

Do this:

        $timeout(function() {
            scope.foo.hero = '';
        });

since the model of your select is foo.hero whenever you change it then the select will change the selected.

回答3:

Not sure why you need to muck around with modelController? Can't you just update the model to the default value?

myApp.directive('myDirective', function($timeout) {
    return {
        scope: {
            model: '=?ngModel'
        },
        link: function(scope, element, attrs, ctlrs) {
            $timeout(function() {
                scope.model = '';
            });
        }
    };
});

Updated fiddle here.

来源：https://stackoverflow.com/questions/24411820/select-the-blank-option-of-select-box-programmatically-in-angularjs-directive

标签

javascript

angularjs

angularjs-directive