在 ng-options 中为选项添加动态 id

Question

当我在select 中使用ng-options 循环我的列表并生成我的下拉列表时，是否可以将动态属性id 添加到option？如果我使用ng-repeat 循环，它会起作用，因为在那里我可以将属性id 直接放在option 标记中，并用$index 递增它。 ng-options 也可以这样做吗？这是我的代码：

angular.module("myApp", []).controller("myController", function($scope) {
  $scope.selectedOption1;
  $scope.selectedOption2;

  $scope.myList = [{
    text: "1"
  }, {
    text: "2"
  }, {
    text: "3"
  }, {
    text: "4"
  }, {
    text: "5"
  }, ];
});

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>

<div ng-app="myApp" ng-controller="myController">
  <!--BUILD DROPDOWN WITH NG-OPTIONS LOOP-->
  <select ng-model="selectedOption" ng-options="option as option.text for option in myList"></select>

  <!--BUILD DROPDOWN AND SET ATTRIBUT ID WITH NG-REPEAT LOOP-->
  <select ng-model="selectedOption2">
    <option id="option_{{$index}}" ng-repeat="option in myList">{{option.text}}</option>
  </select>
</div>

select 的屏幕截图（红色边框是 id）：

有什么想法吗？谢谢。

Answer 1

请看下面的答案。

Angular 将始终将值呈现为index，从0 开始。不要担心这个。因为它将有一个内部引用，并会相应地更新模态。

我在下方放置了一个span 以查看所选项目的value。

angular.module("myApp", []).controller("myController", function($scope) {
  $scope.selectedOption1;
  $scope.selectedOption2;

  $scope.myList = [{
    text: "1"
  }, {
    text: "2"
  }, {
    text: "3"
  }, {
    text: "4"
  }, {
    text: "5"
  }, ];
});

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>

<div ng-app="myApp" ng-controller="myController">
  <!--BUILD DROPDOWN WITH NG-OPTIONS LOOP-->
  <select ng-model="selectedOption" ng-options="('option_' + (myList.indexOf(option) + 1)) as option.text for option in myList"></select>
  <br/><br/>
  Selected: <span><b>{{selectedOption}}</b></span>

</div>

Answer 2

您可以使用track by 选项：

<select ng-model="selectedOption" ng-options="obj.text for obj in myList track by obj.value">

但是，你必须稍微修改你的对象：

$scope.myList = [{
    text: "1",
    value: "option_1"
}, {
    text: "2",
    value: "option_2"
}, {
    text: "3",
    value: "option_3"
}, {
    text: "4",
    value: "option_4"
}, {
    text: "5",
    value: "option_5"
}, ];

这应该可以解决问题。

编辑 The plunker to test it

EDIT 2对于那些想要快速回答的人，您也可以这样做：

<select ng-model="selectedOption" ng-options="obj.text for obj in myList track by option + obj.text">

并在js文件中添加：

$scope.option = 'option_';
$scope.myList = [{
    text: "1"
}, {
    text: "2"
}, {
    text: "3"
}, {
    text: "4"
}, {
    text: "5"
}, ];

Answer 3

angular.module("myApp", []).controller("myController", function($scope) {
  $scope.selectedOption1;
  $scope.selectedOption2;

  $scope.myList = [{
    text: "1"
  }, {
    text: "2"
  }, {
    text: "3"
  }, {
    text: "4"
  }, {
    text: "5"
  }, ];
});

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>

<div ng-app="myApp" ng-controller="myController">
    
<select ng-model="selectedOption2">
 <option ng-repeat="d in myList track by $index" ng-value="'Option_'+($index+1)">
   {{d.text}}
 </option>
  
</select>
  {{selectedOption2}}
</div>