javascript - Angular ng-selected，选择当前父级$index

Question

http://plnkr.co/edit/fwwAd4bn6z2vxVN2FUL7?p=preview

在plunker中你可以看到我想要的，我希望3个下拉列表具有值A、B、C，如果我添加第四个，它应该具有A、B、C、D，当你打开下拉列表时列表中您可以选择所有添加的字母。

<option ng-repeat="n in characters" ng-selected="$index == $parent.$index">{{n}}</option>

所以当你按ADD时你应该选择ABC..并且它应该保持选中状态..但它不会，我如何让它被选中？

Answer 1

您应该使用ng-options您选择的指令。

HTML:

<div ng-app="app">
    <div ng-controller="mainController">
        <div ng-repeat="selected in selecteds track by $index">
            <select ng-model="selecteds[$index]" ng-options="character for character in characters">
            </select>
        </div>
        <button ng-click="addValue()">Add</button>
        <pre ng-bind="characters | json"></pre>
        <pre ng-bind="selecteds | json"></pre>
    </div>
</div>

JS:

angular.module('app', [])
.controller('mainController', function($scope) {
    $scope.characters = ["A", "B", "C"];
    $scope.selecteds = ["A", "B", "C"];
    $scope.addValue = function() { 
        var currGroup = String.fromCharCode(65 + $scope.characters.length);
        $scope.characters.push(currGroup);
    }
});

在这里工作 fiddle :http://jsfiddle.net/ben1729/djy5ooed/