How to get an Array with just the values from selected checkboxes?

问题

How can I bind checkboxes to an array in my model, so that the array always contains just the values corresponding to the selected checkboxes?

For example, instead of:

"groups": { "name1": true, "name2": false, "name3": true }

I need to get:

 "groups": [ "name1", "name3" ]

I browsed through a lot of questions and some answers suggested using ng-true for getting custom values, but that does not solve the problem, because then I get:

"groups": { "name1": 'CustomvalueIset', "name2": 'CustomValueIset', "name3": 'CustomValueIset' }

My current code looks like this:

<div class="form-group">
   <label class="control-label" for="group">Groups</label><br/>
   <label class="checkboxes-br" data-ng-repeat="group in groups">
       <input type="checkbox" id="group" data-ng-model="model.groups[group.name]">
       {{group.name}}
   </label>
</div>

回答1:

There is no native support in AngularJS for checkboxes adding/removing values from an array. There cannot be, because form control model-view binding is managed by ngModel, which requires the control (input) to bind its value to a separate assignable expression (so there's no way to make ngModel delete a value when the checkbox is unchecked).

Don't Mind undefined

You can either solve this by making model.groups an Array and using doing the following code:

<label ng-repeat="group in groups">
    <input type="checkbox" ng-model="model.groups[$index]" ng-true-value="group.name" ng-false-value="undefined">
    ...
</label>

and then filter out the undefineds when using the array.

Computed Property

Or you can just assign the boolean true/false values to an object and set a $watch on that object that automatically updates your array.

<input type="checkbox" ng-model="model.groupFlags[group.name]">

+

var groups = $scope.model.groups = [];
$scope.$watch('model.groupFlags', function (flags) {
    groups.length = 0;
    for (var key in flags) {
        groups.push(key);
    }
}, true);

---

Original answer (the question was unclear):

The documentation suggests that ng-true-value and ng-false-value should work just fine:

<input type="checkbox" ng-model="..." ng-true-value="group.name" ng-false-value="''">

回答2:

Use an ng-click or cg-change handler that adds/removes values from the array.

来源：https://stackoverflow.com/questions/27421619/how-to-get-an-array-with-just-the-values-from-selected-checkboxes