我已经搜索了谷歌,在这个上面什么也找不到。

我有这个代码。

<select ng-model="somethingHere" 
        ng-options="option.value as option.name for option in options"
></select>

有这样的数据

options = [{
   name: 'Something Cool',
   value: 'something-cool-value'
}, {
   name: 'Something Else',
   value: 'something-else-value'
}];

输出是这样的。

<select ng-model="somethingHere"  
        ng-options="option.value as option.name for option in options" 
        class="ng-pristine ng-valid">

    <option value="?" selected="selected"></option>
    <option value="0">Something Cool</option>
    <option value="1">Something Else</option>
</select>

如何将数据中的第一个选项设置为默认值,从而得到这样的结果呢?

<select ng-model="somethingHere" ....>
    <option value="0" selected="selected">Something Cool</option>
    <option value="1">Something Else</option>
</select>

当前回答

Srivathsa Harish Venkataramana只有一个回答提到了轨道,这确实是一个解决方案!

下面是一个关于如何在select ng-options中使用track by的例子(链接如下):

<select ng-model="selectedCity"
        ng-options="city as city.name for city in cities track by city.id">
  <option value="">-- Select City --</option>
</select>

如果selectedCity定义在angular作用域上,并且它的id属性与cities列表中任何城市的id值相同,它将在加载时自动选择。

下面是普伦克的解释: http://plnkr.co/edit/1EVs7R20pCffewrG0EmI?p=preview

有关更多细节,请参阅源代码文档: https://code.angularjs.org/1.3.15/docs/api/ng/directive/select

其他回答

Srivathsa Harish Venkataramana只有一个回答提到了轨道,这确实是一个解决方案!

下面是一个关于如何在select ng-options中使用track by的例子(链接如下):

<select ng-model="selectedCity"
        ng-options="city as city.name for city in cities track by city.id">
  <option value="">-- Select City --</option>
</select>

如果selectedCity定义在angular作用域上,并且它的id属性与cities列表中任何城市的id值相同,它将在加载时自动选择。

下面是普伦克的解释: http://plnkr.co/edit/1EVs7R20pCffewrG0EmI?p=preview

有关更多细节,请参阅源代码文档: https://code.angularjs.org/1.3.15/docs/api/ng/directive/select

根据您拥有的选项的数量,您可以将值放在一个数组中,并像这样自动填充选项

<select ng-model="somethingHere.values" ng-options="values for values in [5,4,3,2,1]">
   <option value="">Pick a Number</option>
</select>

对于Ben Lesh的回答,应该有这样一条线

ng-init="somethingHere = somethingHere || options[0]" 

而不是

ng-init="somethingHere = somethingHere || options[0].value" 

也就是说,

<选择ng-model = " somethingHere " ng-init="somethingHere = somethingHere || options[0]" Ng-options ="option.name for options track by option.value"> < /选择>

如果你有一些东西,而不仅仅是init日期部分,你可以使用ng-init()通过在你的控制器中声明它,并在你的HTML顶部使用它。 这个函数将像控制器的构造函数一样工作,你可以在那里初始化变量。

angular.module('myApp', [])
 .controller('myController', ['$scope', ($scope) => {
   $scope.allOptions = [
     { name: 'Apple', value: 'apple' }, 
     { name: 'Banana', value: 'banana' }
   ];
   $scope.myInit = () => {
      $scope.userSelected = 'apple'
      // Other initiations can goes here..
   }
}]);


<body ng-app="myApp">
  <div ng-controller="myController" ng-init="init()">
    <select ng-model="userSelected" ng-options="option.value as option.name for option in allOptions"></select>
   </div>
</body>
    <!--
    Using following solution you can set initial 
default value at controller as well as after change option selected value shown as default.
    -->
    <script type="text/javascript">
      function myCtrl($scope)
        {
          //...
            $scope.myModel=Initial Default Value; //set default value as required
          //..
        }
    </script>
    <select ng-model="myModel" 
                ng-init="myModel= myModel"
                ng-options="option.value as option.name for option in options">
        </select>